/* ============================================================
   食品化学虚拟实训平台 — 全局样式 v2 (Soft UI Evolution)
   职业教育风格：科技蓝 + 食品安全绿 + 柔和UI
   参考：ui-ux-pro-max 设计系统 + 2.5D精细器皿风格
   ============================================================ */

:root {
  /* 主色系 (Soft UI Evolution) */
  --primary: #2563EB;
  --primary-dark: #1D4ED8;
  --primary-light: #3B82F6;
  --primary-50: #EFF6FF;
  --primary-100: #DBEAFE;
  --accent: #059669;        /* 食品安全绿（更专业） */
  --accent-dark: #047857;
  --accent-light: #10B981;
  --accent-50: #ECFDF5;
  --success: #22C55E;
  --success-dark: #16A34A;
  --warning: #F59E0B;
  --warning-dark: #D97706;
  --danger: #DC2626;        /* 更深沉的错误红 */
  --danger-dark: #B91C1C;
  --info: #0EA5E9;

  /* 背景色（更柔和的灰白） */
  --bg-page: #F8FAFC;
  --bg-card: #FFFFFF;
  --bg-card-translucent: rgba(255, 255, 255, 0.96);
  --bg-tertiary: #F1F5F9;
  --bg-hover: #EFF6FF;
  --bg-muted: #F1F5FD;

  /* 文字色（对比度提升，WCAG AA+） */
  --text-primary: #0F172A;
  --text-secondary: #334155;
  --text-muted: #64748B;
  --text-inverse: #FFFFFF;

  /* 边框（更柔和） */
  --border: #E4ECFC;
  --border-light: #F1F5F9;
  --border-strong: #CBD5E1;

  /* Soft UI 阴影系统（柔和但有层次） */
  --shadow-sm: 0 1px 2px 0 rgba(15, 23, 42, 0.04), 0 1px 3px 0 rgba(15, 23, 42, 0.06);
  --shadow: 0 1px 3px 0 rgba(15, 23, 42, 0.05), 0 4px 6px -1px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.07), 0 2px 4px -2px rgba(15, 23, 42, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(15, 23, 42, 0.1), 0 8px 10px -6px rgba(15, 23, 42, 0.05);
  --shadow-2xl: 0 25px 50px -12px rgba(15, 23, 42, 0.18);
  --shadow-blue: 0 4px 14px rgba(37, 99, 235, 0.2), 0 2px 6px rgba(37, 99, 235, 0.12);
  --shadow-green: 0 4px 14px rgba(5, 150, 105, 0.2), 0 2px 6px rgba(5, 150, 105, 0.12);
  --shadow-red: 0 4px 14px rgba(220, 38, 38, 0.2), 0 2px 6px rgba(220, 38, 38, 0.12);
  /* Soft UI 内凹阴影（用于立体感） */
  --shadow-inset: inset 0 1px 2px rgba(15, 23, 42, 0.06), inset 0 -1px 1px rgba(255, 255, 255, 0.8);
  --shadow-soft: 0 2px 8px rgba(15, 23, 42, 0.06), 0 1px 2px rgba(15, 23, 42, 0.04);

  /* 圆角 */
  --radius-sm: 10px;
  --radius: 14px;
  --radius-md: 18px;
  --radius-lg: 22px;
  --radius-xl: 28px;

  /* 字号统一（WCAG AA+，正文不低于16px） */
  --fs-hero: 32px;         /* 主标题 */
  --fs-module: 26px;       /* 模块标题 */
  --fs-section: 22px;      /* 小节标题 */
  --fs-body: 17px;         /* 正文 */
  --fs-btn: 17px;          /* 按钮文字 */
  --fs-label: 16px;        /* 标签 */
  --fs-data: 32px;         /* 重要数据 */
  --fs-data-lg: 38px;      /* 大号数据 */
  --fs-small: 15px;        /* 小字 */
  --fs-micro: 14px;        /* 最小字号（仅辅助信息） */

  /* 间距（Soft UI 标准） */
  --gap-xs: 8px;
  --gap-sm: 12px;
  --gap-md: 20px;
  --gap-lg: 28px;
  --gap-xl: 40px;

  /* 过渡（150-300ms，Soft UI 标准） */
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);

  /* 玻璃器皿配色（2.5D精细风格） */
  --glass-border: #475569;
  --glass-border-light: #64748B;
  --glass-fill: rgba(220, 235, 255, 0.18);
  --glass-highlight: rgba(255, 255, 255, 0.55);
  --glass-shadow: rgba(100, 116, 139, 0.15);
  --glass-shadow-dark: rgba(71, 85, 105, 0.25);
  /* 液体配色 */
  --liquid-blue: rgba(59, 130, 246, 0.65);
  --liquid-blue-dark: rgba(37, 99, 235, 0.85);
  --liquid-green: rgba(34, 197, 94, 0.6);
  --liquid-red: rgba(239, 68, 68, 0.6);
  --liquid-yellow: rgba(245, 158, 11, 0.65);
  --liquid-purple: rgba(139, 92, 246, 0.6);
  --liquid-orange: rgba(249, 115, 22, 0.65);
  --liquid-brown: rgba(120, 53, 15, 0.7);
  --liquid-clear: rgba(220, 235, 255, 0.15);
}

/* ============================================================
   基础重置
   ============================================================ */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: "Inter", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", Arial, sans-serif;
  background: var(--bg-page);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ============================================================
   布局容器
   ============================================================ */
.container {
  max-width: 1440px;
  margin: 0 auto;
  padding: var(--gap-md);
}

/* ============================================================
   顶部 Header
   ============================================================ */
.header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: var(--text-inverse);
  padding: 36px 40px;
  border-radius: var(--radius-lg);
  margin-bottom: var(--gap-md);
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

.header::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -10%;
  width: 400px;
  height: 400px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 50%;
}

.header::after {
  content: "";
  position: absolute;
  bottom: -30%;
  left: 20%;
  width: 200px;
  height: 200px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 50%;
}

.header h1 {
  font-size: var(--fs-hero);
  font-weight: 700;
  margin-bottom: var(--gap-sm);
  position: relative;
  z-index: 1;
  letter-spacing: 0.5px;
}

.header p {
  font-size: var(--fs-body);
  opacity: 0.92;
  position: relative;
  z-index: 1;
}

.header .back-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--gap-xs);
  background: rgba(255, 255, 255, 0.18);
  color: var(--text-inverse);
  border: 1.5px solid rgba(255, 255, 255, 0.25);
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--fs-label);
  font-weight: 500;
  margin-bottom: var(--gap-md);
  transition: var(--transition);
  position: relative;
  z-index: 1;
}

.header .back-btn:hover {
  background: rgba(255, 255, 255, 0.3);
  border-color: rgba(255, 255, 255, 0.4);
}

.header .back-btn:focus-visible {
  outline: 3px solid rgba(255, 255, 255, 0.5);
  outline-offset: 2px;
}

/* Header 工具栏 */
.header-toolbar {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  margin-top: var(--gap-md);
  position: relative;
  z-index: 1;
  flex-wrap: wrap;
}

.header-toolbar .tool-btn {
  background: rgba(255, 255, 255, 0.15);
  color: var(--text-inverse);
  border: 1.5px solid rgba(255, 255, 255, 0.2);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--fs-label);
  font-weight: 500;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.header-toolbar .tool-btn:hover {
  background: rgba(255, 255, 255, 0.28);
}

/* ============================================================
   主布局：左侧步骤导航 + 右侧内容
   ============================================================ */
.main-layout {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: var(--gap-md);
}

.sidebar {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: var(--gap-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  height: fit-content;
  position: sticky;
  top: var(--gap-md);
}

.sidebar-title {
  font-size: var(--fs-section);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--gap-md);
  padding-bottom: var(--gap-sm);
  border-bottom: 2px solid var(--border-light);
}

/* 步骤列表 */
.step-list {
  list-style: none;
}

.step-item {
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  margin-bottom: var(--gap-xs);
  cursor: pointer;
  transition: var(--transition-fast);
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  font-size: var(--fs-body);
  font-weight: 500;
  color: var(--text-secondary);
  border: 2px solid transparent;
}

.step-item:hover {
  background: var(--bg-hover);
  border-color: var(--border-light);
}

.step-item.active {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: var(--text-inverse);
  border-color: transparent;
  box-shadow: var(--shadow-blue);
}

.step-item.completed {
  color: var(--success-dark);
  background: rgba(34, 197, 94, 0.08);
}

.step-item.completed .step-number {
  background: var(--success);
  color: var(--text-inverse);
}

.step-item:focus-visible {
  outline: 3px solid var(--primary-light);
  outline-offset: 2px;
}

.step-number {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--fs-label);
  flex-shrink: 0;
  transition: var(--transition-fast);
}

.step-item.active .step-number {
  background: rgba(255, 255, 255, 0.25);
}

.step-item.completed .step-number {
  background: var(--success);
  color: var(--text-inverse);
}

/* 进度条 */
.progress-bar {
  height: 12px;
  background: var(--bg-tertiary);
  border-radius: 6px;
  overflow: hidden;
  margin: var(--gap-sm) 0;
  border: 1px solid var(--border-light);
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary) 0%, var(--primary-light) 100%);
  border-radius: 6px;
  transition: width 0.5s ease;
}

.progress-fill.success {
  background: linear-gradient(90deg, var(--success) 0%, var(--success-dark) 100%);
}

.progress-fill.warning {
  background: linear-gradient(90deg, var(--warning) 0%, var(--warning-dark) 100%);
}

.progress-fill.danger {
  background: linear-gradient(90deg, var(--danger) 0%, var(--danger-dark) 100%);
}

.progress-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--fs-label);
  color: var(--text-secondary);
  font-weight: 600;
  margin-bottom: 6px;
}

.progress-percent {
  font-size: var(--fs-data);
  font-weight: 700;
  color: var(--primary);
}

.progress-percent.success {
  color: var(--success);
}

/* ============================================================
   内容区域
   ============================================================ */
.content-area {
  min-height: 600px;
}

/* ============================================================
   卡片
   ============================================================ */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: var(--gap-lg);
  box-shadow: var(--shadow-sm);
  margin-bottom: var(--gap-md);
  border: 1px solid var(--border-light);
  transition: var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card-title {
  font-size: var(--fs-module);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--gap-md);
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
}

.card-title .icon {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-inverse);
  font-size: var(--fs-body);
  flex-shrink: 0;
  box-shadow: var(--shadow-blue);
}

.section-title {
  font-size: var(--fs-section);
  font-weight: 700;
  color: var(--text-primary);
  margin: var(--gap-md) 0 var(--gap-sm);
  padding-left: 14px;
  border-left: 5px solid var(--primary);
}

/* ============================================================
   表单
   ============================================================ */
.form-group {
  margin-bottom: var(--gap-md);
}

.form-label {
  display: block;
  font-size: var(--fs-label);
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: var(--gap-xs);
}

.form-input {
  width: 100%;
  padding: 14px 18px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: var(--fs-body);
  font-family: inherit;
  transition: var(--transition-fast);
  background: var(--bg-page);
  color: var(--text-primary);
}

.form-input:focus {
  outline: none;
  border-color: var(--primary);
  background: var(--bg-card);
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.12);
}

.form-input:focus-visible {
  outline: none;
}

.form-input::placeholder {
  color: var(--text-muted);
}

.form-input.error {
  border-color: var(--danger);
  background: rgba(239, 68, 68, 0.04);
}

.form-input.success {
  border-color: var(--success);
}

.form-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--gap-md);
}

/* ============================================================
   按钮 — 高度≥48px, 圆角14px, 字号18px
   ============================================================ */
.btn {
  padding: 14px 28px;
  min-height: 48px;
  border-radius: var(--radius);
  font-size: var(--fs-btn);
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--gap-xs);
  letter-spacing: 0.3px;
}

.btn:focus-visible {
  outline: 3px solid var(--primary-light);
  outline-offset: 2px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: var(--text-inverse);
  box-shadow: var(--shadow-blue);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.35);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-primary:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 2px solid var(--border);
}

.btn-secondary:hover {
  background: var(--border-light);
  border-color: var(--text-muted);
}

.btn-success {
  background: linear-gradient(135deg, var(--success) 0%, var(--success-dark) 100%);
  color: var(--text-inverse);
  box-shadow: var(--shadow-green);
}

.btn-success:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(34, 197, 94, 0.35);
}

.btn-danger {
  background: linear-gradient(135deg, var(--danger) 0%, var(--danger-dark) 100%);
  color: var(--text-inverse);
  box-shadow: var(--shadow-red);
}

.btn-danger:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(239, 68, 68, 0.35);
}

.btn-warning {
  background: linear-gradient(135deg, var(--warning) 0%, var(--warning-dark) 100%);
  color: var(--text-inverse);
}

.btn-warning:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(245, 158, 11, 0.35);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}

.btn-outline:hover {
  background: rgba(37, 99, 235, 0.08);
}

.btn-group {
  display: flex;
  gap: var(--gap-sm);
  flex-wrap: wrap;
}

/* 底部导航按钮 */
.btn-nav {
  display: flex;
  justify-content: space-between;
  margin-top: var(--gap-md);
  padding-top: var(--gap-md);
  border-top: 2px solid var(--border-light);
  gap: var(--gap-sm);
  flex-wrap: wrap;
}

.btn-nav .btn {
  min-width: 140px;
}

/* ============================================================
   数据表格
   ============================================================ */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--gap-sm) 0;
  font-size: var(--fs-body);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.data-table th,
.data-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border-light);
}

.data-table th {
  background: var(--bg-tertiary);
  font-weight: 700;
  color: var(--text-secondary);
  font-size: var(--fs-label);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.data-table tr:hover td {
  background: var(--bg-hover);
}

.data-table .highlight {
  background: rgba(37, 99, 235, 0.05);
  font-weight: 700;
  color: var(--primary);
}

/* ============================================================
   结果框
   ============================================================ */
.result-box {
  background: linear-gradient(135deg, rgba(34, 197, 94, 0.08) 0%, rgba(20, 184, 166, 0.08) 100%);
  border: 1.5px solid rgba(34, 197, 94, 0.2);
  border-radius: var(--radius-md);
  padding: var(--gap-lg);
  margin: var(--gap-md) 0;
}

.result-box.warning {
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.08) 0%, rgba(239, 68, 68, 0.06) 100%);
  border-color: rgba(245, 158, 11, 0.25);
}

.result-box.error {
  background: linear-gradient(135deg, rgba(239, 68, 68, 0.08) 0%, rgba(239, 68, 68, 0.12) 100%);
  border-color: rgba(239, 68, 68, 0.25);
}

.result-title {
  font-size: var(--fs-section);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--gap-sm);
  display: flex;
  align-items: center;
  gap: var(--gap-xs);
}

.result-value {
  font-size: var(--fs-data-lg);
  font-weight: 800;
  color: var(--success);
  margin: var(--gap-xs) 0;
}

.result-box.warning .result-value {
  color: var(--warning-dark);
}

.result-box.error .result-value {
  color: var(--danger);
}

.result-desc {
  font-size: var(--fs-label);
  color: var(--text-secondary);
  margin-top: var(--gap-xs);
}

/* ============================================================
   弹窗/模态框
   ============================================================ */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

.modal-overlay.show {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 36px;
  max-width: 520px;
  width: 90%;
  transform: scale(0.9) translateY(20px);
  transition: var(--transition);
  box-shadow: var(--shadow-xl);
}

.modal-overlay.show .modal {
  transform: scale(1) translateY(0);
}

.modal-header {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  margin-bottom: var(--gap-md);
}

.modal-icon {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  flex-shrink: 0;
}

.modal-icon.error {
  background: rgba(239, 68, 68, 0.12);
  color: var(--danger);
}

.modal-icon.warning {
  background: rgba(245, 158, 11, 0.12);
  color: var(--warning-dark);
}

.modal-icon.success {
  background: rgba(34, 197, 94, 0.12);
  color: var(--success);
}

.modal-icon.info {
  background: rgba(14, 165, 233, 0.12);
  color: var(--info);
}

.modal-title {
  font-size: var(--fs-section);
  font-weight: 700;
  color: var(--text-primary);
}

.modal-body {
  color: var(--text-secondary);
  font-size: var(--fs-body);
  line-height: 1.8;
  margin-bottom: var(--gap-lg);
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--gap-sm);
}

/* ============================================================
   标签
   ============================================================ */
.tag {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 22px;
  font-size: var(--fs-label);
  font-weight: 600;
  letter-spacing: 0.2px;
}

.tag-primary {
  background: rgba(37, 99, 235, 0.1);
  color: var(--primary);
}

.tag-success {
  background: rgba(34, 197, 94, 0.1);
  color: var(--success-dark);
}

.tag-warning {
  background: rgba(245, 158, 11, 0.1);
  color: var(--warning-dark);
}

.tag-danger {
  background: rgba(239, 68, 68, 0.1);
  color: var(--danger);
}

.tag-info {
  background: rgba(14, 165, 233, 0.1);
  color: var(--info);
}

.tag-accent {
  background: rgba(20, 184, 166, 0.1);
  color: var(--accent-dark);
}

/* ============================================================
   实验卡片网格（首页）
   ============================================================ */
.experiments-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
  gap: var(--gap-md);
}

.experiment-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--gap-lg);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border: 1px solid var(--border-light);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.experiment-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: linear-gradient(90deg, var(--primary) 0%, var(--accent) 100%);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.experiment-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-light);
}

.experiment-card:hover::before {
  transform: scaleX(1);
}

.experiment-card:focus-visible {
  outline: 3px solid var(--primary-light);
  outline-offset: 2px;
}

.experiment-card .exp-number {
  width: 54px;
  height: 54px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: var(--text-inverse);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--fs-section);
  font-weight: 800;
  margin-bottom: var(--gap-md);
  box-shadow: var(--shadow-blue);
}

.experiment-card h3 {
  font-size: var(--fs-section);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--gap-xs);
}

.experiment-card p {
  font-size: var(--fs-body);
  color: var(--text-secondary);
  margin-bottom: var(--gap-md);
  line-height: 1.7;
}

.experiment-card .exp-meta {
  display: flex;
  gap: var(--gap-xs);
  flex-wrap: wrap;
}

/* ============================================================
   实验操作区 / 仪器可视化区
   ============================================================ */
.lab-area {
  background: linear-gradient(180deg, #F0F9FF 0%, #E0F2FE 100%);
  border-radius: var(--radius-md);
  padding: var(--gap-lg);
  margin: var(--gap-md) 0;
  min-height: 300px;
  position: relative;
  border: 2px dashed var(--info);
}

.lab-bench {
  background: #8b5a2b;
  height: 24px;
  border-radius: 4px 4px 0 0;
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
}

.instrument {
  position: relative;
  cursor: pointer;
  transition: var(--transition);
}

.instrument:hover {
  transform: scale(1.05);
}

/* 滴定管（2.5D精细风格，玻璃高光+刻度） */
.burette {
  width: 32px;
  height: 210px;
  background: linear-gradient(90deg, rgba(180, 200, 230, 0.25) 0%, rgba(255, 255, 255, 0.6) 35%, rgba(240, 248, 255, 0.4) 60%, rgba(180, 200, 230, 0.2) 100%);
  border: 2.5px solid #334155;
  border-radius: 5px 5px 2px 2px;
  position: relative;
  margin: 0 auto;
  box-shadow: inset 2px 0 4px rgba(255, 255, 255, 0.5), inset -2px 0 4px var(--glass-shadow), var(--shadow-soft);
}

/* 滴定管高光条 */
.burette::before {
  content: "";
  position: absolute;
  top: 4px;
  left: 4px;
  width: 4px;
  height: calc(100% - 8px);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.7) 0%, rgba(255, 255, 255, 0.3) 100%);
  border-radius: 2px;
  z-index: 3;
  pointer-events: none;
}

.burette-tip {
  width: 11px;
  height: 32px;
  background: linear-gradient(90deg, rgba(180, 200, 230, 0.25) 0%, rgba(255, 255, 255, 0.6) 50%, rgba(180, 200, 230, 0.2) 100%);
  border: 2px solid var(--glass-border);
  border-top: none;
  border-radius: 0 0 5px 5px;
  position: absolute;
  bottom: -32px;
  left: 50%;
  transform: translateX(-50%);
  box-shadow: inset 1px 0 2px rgba(255, 255, 255, 0.4), inset -1px 0 2px var(--glass-shadow);
}

.burette-liquid {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: linear-gradient(180deg, var(--liquid-blue) 0%, var(--liquid-blue-dark) 100%);
  border-radius: 0 0 2px 2px;
  transition: height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: inset 0 2px 4px rgba(255, 255, 255, 0.3);
}

/* 液面凹面反光 */
.burette-liquid::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.5) 0%, transparent 100%);
  border-radius: 50%;
}

.burette-scale {
  position: absolute;
  right: -32px;
  top: 0;
  height: 100%;
  width: 28px;
  font-size: 11px;
  color: var(--text-muted);
  font-family: "Courier New", monospace;
}

/* 锥形瓶（2.5D精细风格，梯形+玻璃质感） */
.flask {
  width: 130px;
  height: 160px;
  position: relative;
  filter: drop-shadow(0 4px 6px var(--glass-shadow));
}

.flask-body {
  width: 130px;
  height: 110px;
  background: linear-gradient(135deg, rgba(200, 220, 245, 0.18) 0%, rgba(255, 255, 255, 0.45) 35%, rgba(220, 235, 250, 0.25) 65%, rgba(180, 200, 230, 0.15) 100%);
  border: 2.5px solid #334155;
  border-radius: 0 0 65px 65px;
  position: absolute;
  bottom: 0;
  left: 0;
  overflow: hidden;
  box-shadow: inset 6px -4px 12px rgba(255, 255, 255, 0.3), inset -4px 4px 8px var(--glass-shadow);
}

/* 锥形瓶左侧高光 */
.flask-body::before {
  content: "";
  position: absolute;
  top: 10px;
  left: 12px;
  width: 8px;
  height: 70%;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.6) 0%, rgba(255, 255, 255, 0.2) 100%);
  border-radius: 50%;
  filter: blur(1px);
}

.flask-neck {
  width: 32px;
  height: 52px;
  background: linear-gradient(135deg, rgba(200, 220, 245, 0.18) 0%, rgba(255, 255, 255, 0.45) 35%, rgba(220, 235, 250, 0.25) 65%, rgba(180, 200, 230, 0.15) 100%);
  border: 2px solid var(--glass-border);
  border-bottom: none;
  border-radius: 5px 5px 0 0;
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  box-shadow: inset 2px 0 3px rgba(255, 255, 255, 0.4), inset -2px 0 3px var(--glass-shadow);
}

/* 瓶口边缘加粗 */
.flask-neck::after {
  content: "";
  position: absolute;
  top: -2px;
  left: -4px;
  right: -4px;
  height: 5px;
  background: linear-gradient(90deg, var(--glass-border) 0%, var(--glass-border-light) 50%, var(--glass-border) 100%);
  border-radius: 3px;
}

.flask-liquid {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: linear-gradient(180deg, var(--liquid-blue) 0%, var(--liquid-blue-dark) 100%);
  border-radius: 0 0 60px 60px;
  transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: inset 0 3px 6px rgba(255, 255, 255, 0.25);
}

/* 液面反光 */
.flask-liquid::before {
  content: "";
  position: absolute;
  top: 0;
  left: 10%;
  right: 10%;
  height: 4px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.5) 0%, transparent 100%);
  border-radius: 50%;
}

/* 试管架 */
.tube-rack {
  display: flex;
  gap: var(--gap-sm);
  justify-content: center;
  padding: var(--gap-md);
  background: linear-gradient(180deg, #d4a574 0%, #b8895a 100%);
  border-radius: var(--radius-sm);
  width: fit-content;
  margin: 0 auto;
  box-shadow: var(--shadow-md), inset 0 1px 2px rgba(255, 255, 255, 0.3);
}

/* 试管（2.5D精细风格） */
.test-tube {
  width: 32px;
  height: 130px;
  background: linear-gradient(90deg, rgba(180, 200, 230, 0.22) 0%, rgba(255, 255, 255, 0.55) 35%, rgba(240, 248, 255, 0.35) 60%, rgba(180, 200, 230, 0.18) 100%);
  border: 2.5px solid #334155;
  border-radius: 5px 5px 16px 16px;
  position: relative;
  overflow: hidden;
  box-shadow: inset 2px 0 3px rgba(255, 255, 255, 0.5), inset -2px 0 3px var(--glass-shadow), var(--shadow-sm);
}

/* 试管高光 */
.test-tube::before {
  content: "";
  position: absolute;
  top: 5px;
  left: 4px;
  width: 5px;
  height: 80%;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.7) 0%, rgba(255, 255, 255, 0.2) 100%);
  border-radius: 50%;
  z-index: 2;
  pointer-events: none;
}

.test-tube-liquid {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: inset 0 2px 4px rgba(255, 255, 255, 0.3);
}

/* 颜色类 */
.color-blue { background: rgba(59, 130, 246, 0.6); }
.color-red { background: rgba(239, 68, 68, 0.6); }
.color-green { background: rgba(34, 197, 94, 0.6); }
.color-yellow { background: rgba(245, 158, 11, 0.6); }
.color-purple { background: rgba(139, 92, 246, 0.6); }
.color-orange { background: rgba(249, 115, 22, 0.6); }
.color-brown { background: rgba(120, 53, 15, 0.6); }
.color-clear { background: rgba(200, 200, 255, 0.1); }

/* 仪器行 */
.equipment-row {
  display: flex;
  justify-content: center;
  align-items: flex-end;
  gap: 40px;
  margin: 40px 0;
  flex-wrap: wrap;
}

.equipment-item {
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  padding: var(--gap-sm);
  border-radius: var(--radius-sm);
}

.equipment-item:hover {
  background: rgba(37, 99, 235, 0.05);
  transform: translateY(-4px);
}

.equipment-item.active {
  background: rgba(37, 99, 235, 0.1);
  box-shadow: 0 0 0 3px var(--primary);
}

.equipment-item .label {
  margin-top: var(--gap-xs);
  font-size: var(--fs-label);
  color: var(--text-secondary);
  font-weight: 600;
}

/* pH计 */
.ph-meter {
  width: 180px;
  background: #334155;
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  color: var(--text-inverse);
  text-align: center;
}

.ph-display {
  background: #0f172a;
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  margin-bottom: var(--gap-sm);
  font-family: "Courier New", monospace;
}

.ph-value {
  font-size: 36px;
  font-weight: 700;
  color: #4ade80;
  text-shadow: 0 0 10px rgba(74, 222, 128, 0.5);
}

.ph-unit {
  font-size: var(--fs-body);
  color: #94a3b8;
}

.ph-probe {
  width: 12px;
  height: 80px;
  background: linear-gradient(90deg, #64748b 0%, #94a3b8 50%, #64748b 100%);
  border-radius: 4px;
  margin: var(--gap-sm) auto 0;
  position: relative;
}

.ph-probe::after {
  content: "";
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 8px;
  height: 15px;
  background: #fbbf24;
  border-radius: 0 0 4px 4px;
}

/* 分光光度计 */
.spectrophotometer {
  width: 220px;
  background: linear-gradient(180deg, #475569 0%, #334155 100%);
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  color: var(--text-inverse);
}

.spec-display {
  background: #0f172a;
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  text-align: center;
  font-family: "Courier New", monospace;
}

.spec-value {
  font-size: 28px;
  font-weight: 700;
  color: #fbbf24;
}

.spec-label {
  font-size: var(--fs-label);
  color: #94a3b8;
  margin-top: 4px;
}

.spec-slot {
  width: 100%;
  height: 60px;
  background: #1e293b;
  border-radius: var(--radius-sm);
  margin-top: var(--gap-md);
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px dashed #475569;
}

.cuvette {
  width: 30px;
  height: 50px;
  background: rgba(200, 200, 255, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 2px;
}

/* 烘箱（2.5D精细风格，金属机身+玻璃视窗） */
.oven {
  width: 165px;
  height: 185px;
  background: linear-gradient(180deg, #94a3b8 0%, #64748b 40%, #475569 100%);
  border-radius: var(--radius-sm);
  position: relative;
  padding: var(--gap-sm);
  box-shadow: var(--shadow-lg), inset 0 1px 2px rgba(255, 255, 255, 0.3), inset 0 -2px 4px rgba(15, 23, 42, 0.2);
}

.oven-door {
  width: 100%;
  height: 125px;
  background: linear-gradient(135deg, #475569 0%, #334155 50%, #1e293b 100%);
  border-radius: 5px;
  border: 3px solid #1e293b;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.3);
}

.oven-window {
  width: 85px;
  height: 65px;
  background: linear-gradient(180deg, rgba(251, 191, 36, 0.4) 0%, rgba(245, 158, 11, 0.25) 100%);
  border: 3px solid #1e293b;
  border-radius: 5px;
  box-shadow: inset 0 0 8px rgba(251, 191, 36, 0.3), inset 2px 2px 4px rgba(255, 255, 255, 0.2);
}

.oven-display {
  background: linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
  padding: var(--gap-xs);
  border-radius: 5px;
  margin-top: var(--gap-xs);
  text-align: center;
  font-family: "Courier New", monospace;
  color: #ef4444;
  font-size: var(--fs-label);
  font-weight: 600;
  text-shadow: 0 0 4px rgba(239, 68, 68, 0.6);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.5);
}

/* 天平（2.5D精细风格，不锈钢机身+LED显示） */
.balance {
  width: 185px;
  background: linear-gradient(180deg, #f1f5f9 0%, #e2e8f0 40%, #cbd5e1 100%);
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  text-align: center;
  box-shadow: var(--shadow-lg), inset 0 1px 2px rgba(255, 255, 255, 0.8), inset 0 -2px 4px rgba(100, 116, 139, 0.2);
}

.balance-display {
  background: linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
  border-radius: var(--radius-sm);
  padding: var(--gap-sm);
  font-family: "Courier New", monospace;
  color: #4ade80;
  font-size: 22px;
  font-weight: 600;
  text-shadow: 0 0 6px rgba(74, 222, 128, 0.5);
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.6);
}

.balance-pan {
  width: 105px;
  height: 22px;
  background: linear-gradient(180deg, #94a3b8 0%, #64748b 50%, #475569 100%);
  border-radius: 50%;
  margin: var(--gap-sm) auto 0;
  box-shadow: 0 2px 4px rgba(15, 23, 42, 0.2), inset 0 1px 1px rgba(255, 255, 255, 0.4);
}

/* 干燥器（2.5D精细风格，玻璃罐+磨砂盖） */
.desiccator {
  width: 105px;
  height: 145px;
  position: relative;
  filter: drop-shadow(0 4px 6px var(--glass-shadow));
}

.desiccator-body {
  width: 105px;
  height: 105px;
  background: linear-gradient(135deg, rgba(200, 220, 245, 0.22) 0%, rgba(255, 255, 255, 0.5) 35%, rgba(220, 235, 250, 0.3) 65%, rgba(180, 200, 230, 0.18) 100%);
  border: 2px solid var(--glass-border);
  border-radius: 50% 50% 12% 12%;
  position: absolute;
  bottom: 0;
  box-shadow: inset 4px -3px 10px rgba(255, 255, 255, 0.3), inset -3px 3px 6px var(--glass-shadow);
}

/* 干燥器高光 */
.desiccator-body::before {
  content: "";
  position: absolute;
  top: 15px;
  left: 18px;
  width: 12px;
  height: 50%;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.6) 0%, rgba(255, 255, 255, 0.15) 100%);
  border-radius: 50%;
  filter: blur(2px);
}

.desiccator-lid {
  width: 85px;
  height: 52px;
  background: linear-gradient(135deg, rgba(220, 235, 250, 0.3) 0%, rgba(255, 255, 255, 0.55) 40%, rgba(200, 220, 245, 0.25) 100%);
  border: 2px solid var(--glass-border);
  border-radius: 50% 50% 0 0;
  position: absolute;
  top: 0;
  left: 10px;
  box-shadow: inset 3px 0 5px rgba(255, 255, 255, 0.4), inset -2px 0 4px var(--glass-shadow);
}

/* 干燥器盖顶旋钮 */
.desiccator-lid::after {
  content: "";
  position: absolute;
  top: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 10px;
  background: linear-gradient(180deg, var(--glass-border-light) 0%, var(--glass-border) 100%);
  border-radius: 50% 50% 2px 2px;
}

/* 层析装置 */
.chromatography {
  width: 200px;
  height: 300px;
  background: white;
  border: 1px solid var(--border);
  position: relative;
  margin: 0 auto;
}

.chromatography-paper {
  position: absolute;
  top: 10px;
  left: 10px;
  right: 10px;
  bottom: 30px;
  background: #fefefe;
  border: 1px solid #e5e5e5;
}

.chromatography-spot {
  position: absolute;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  left: 50%;
  transform: translateX(-50%);
  transition: all 2s ease;
}

.chromatography-solvent {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 30px;
  background: rgba(147, 197, 253, 0.4);
}

.chromatography-front {
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background: rgba(59, 130, 246, 0.5);
  transition: top 2s ease;
}

/* 水分活度仪 */
.aw-meter {
  width: 200px;
  background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%);
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border);
}

.aw-display {
  background: #0f172a;
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  text-align: center;
  font-family: "Courier New", monospace;
}

.aw-value {
  font-size: 32px;
  font-weight: 700;
  color: #4ade80;
  text-shadow: 0 0 10px rgba(74, 222, 128, 0.5);
}

.aw-label {
  font-size: var(--fs-label);
  color: #94a3b8;
  margin-top: 4px;
}

/* 凯氏定氮装置 */
.kjeldahl-apparatus {
  display: flex;
  align-items: flex-end;
  justify-content: center;
  gap: var(--gap-md);
  margin: 30px 0;
}

.digestion-tube {
  width: 50px;
  height: 200px;
  background: linear-gradient(135deg, rgba(180, 200, 230, 0.22) 0%, rgba(255, 255, 255, 0.6) 35%, rgba(220, 235, 250, 0.35) 65%, rgba(180, 200, 230, 0.18) 100%);
  border: 2.5px solid #334155;
  border-radius: 6px 6px 25px 25px;
  position: relative;
  overflow: hidden;
  box-shadow: inset 3px 0 4px rgba(255, 255, 255, 0.6), inset -3px 0 4px var(--glass-shadow), 0 3px 6px rgba(15, 23, 42, 0.1);
}
/* 消化管高光 */
.digestion-tube::before {
  content: "";
  position: absolute;
  top: 8px;
  left: 6px;
  width: 5px;
  height: 80%;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.7) 0%, rgba(255, 255, 255, 0.15) 100%);
  border-radius: 50%;
  z-index: 3;
  pointer-events: none;
}
/* 消化管口边缘 */
.digestion-tube::after {
  content: "";
  position: absolute;
  top: -2px;
  left: -3px;
  right: -3px;
  height: 6px;
  background: linear-gradient(180deg, var(--glass-border-light) 0%, #334155 100%);
  border-radius: 4px;
  z-index: 4;
}

.digestion-liquid {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  transition: all 1s ease;
}

.digestion-heat {
  position: absolute;
  bottom: -20px;
  left: 50%;
  transform: translateX(-50%);
  width: 40px;
  height: 20px;
  background: linear-gradient(180deg, #fbbf24 0%, #ef4444 100%);
  border-radius: 0 0 50% 50%;
  opacity: 0;
  transition: opacity 0.5s;
}

.digestion-heat.active {
  opacity: 1;
  animation: flicker 0.5s infinite alternate;
}

@keyframes flicker {
  0% { transform: translateX(-50%) scaleY(1); }
  100% { transform: translateX(-50%) scaleY(0.9); }
}

/* ============================================================
   提示框 / 注释
   ============================================================ */
.warning-note {
  background: rgba(245, 158, 11, 0.08);
  border-left: 5px solid var(--warning);
  padding: var(--gap-md) var(--gap-lg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: var(--gap-md) 0;
  font-size: var(--fs-body);
  color: var(--text-secondary);
  line-height: 1.8;
}

.info-note {
  background: rgba(14, 165, 233, 0.08);
  border-left: 5px solid var(--info);
  padding: var(--gap-md) var(--gap-lg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: var(--gap-md) 0;
  font-size: var(--fs-body);
  color: var(--text-secondary);
  line-height: 1.8;
}

.success-note {
  background: rgba(34, 197, 94, 0.08);
  border-left: 5px solid var(--success);
  padding: var(--gap-md) var(--gap-lg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: var(--gap-md) 0;
  font-size: var(--fs-body);
  color: var(--text-secondary);
  line-height: 1.8;
}

.danger-note {
  background: rgba(239, 68, 68, 0.08);
  border-left: 5px solid var(--danger);
  padding: var(--gap-md) var(--gap-lg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: var(--gap-md) 0;
  font-size: var(--fs-body);
  color: var(--text-secondary);
  line-height: 1.8;
}

/* 公式框 */
.formula {
  background: var(--bg-tertiary);
  padding: var(--gap-md) var(--gap-lg);
  border-radius: var(--radius-sm);
  font-family: "Times New Roman", "STSong", serif;
  font-size: var(--fs-body);
  text-align: center;
  margin: var(--gap-md) 0;
  font-style: italic;
  color: var(--text-primary);
}

/* 步骤描述 */
.step-desc {
  background: var(--bg-page);
  padding: var(--gap-md) var(--gap-lg);
  border-radius: var(--radius-sm);
  margin-bottom: var(--gap-md);
  font-size: var(--fs-body);
  line-height: 1.8;
  color: var(--text-secondary);
}

.step-desc strong {
  color: var(--text-primary);
}

/* 交互操作区 */
.interactive-area {
  background: linear-gradient(135deg, #F0F9FF 0%, #E0F2FE 100%);
  border-radius: var(--radius-md);
  padding: var(--gap-lg);
  margin: var(--gap-md) 0;
  border: 2px solid rgba(14, 165, 233, 0.3);
}

/* 拖拽 */
.drag-container {
  min-height: 100px;
  border: 2px dashed var(--border);
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  display: flex;
  gap: var(--gap-sm);
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
}

.drag-item {
  padding: 10px 18px;
  background: var(--bg-card);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: grab;
  font-size: var(--fs-label);
  font-weight: 500;
  transition: var(--transition-fast);
  user-select: none;
}

.drag-item:hover {
  border-color: var(--primary);
  background: rgba(37, 99, 235, 0.05);
}

.drag-item.dragging {
  opacity: 0.5;
  cursor: grabbing;
}

.drop-zone {
  min-height: 64px;
  border: 2px dashed var(--primary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(37, 99, 235, 0.02);
  color: var(--text-muted);
  font-size: var(--fs-label);
  transition: var(--transition);
}

.drop-zone.drag-over {
  background: rgba(37, 99, 235, 0.1);
  border-color: var(--primary);
}

/* ============================================================
   动画
   ============================================================ */
.hidden {
  display: none !important;
}

.fade-in {
  animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.slide-up {
  animation: slideUp 0.5s ease;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.pulse {
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

.bubbles {
  position: absolute;
  width: 100%;
  height: 100%;
  overflow: hidden;
  pointer-events: none;
}

.bubble {
  position: absolute;
  bottom: 0;
  width: 8px;
  height: 8px;
  background: rgba(255, 255, 255, 0.6);
  border-radius: 50%;
  animation: rise 2s infinite ease-in;
}

@keyframes rise {
  0% { bottom: 0; opacity: 0; }
  10% { opacity: 1; }
  90% { opacity: 1; }
  100% { bottom: 100%; opacity: 0; }
}

/* ============================================================
   实验报告
   ============================================================ */
.report-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: var(--gap-lg);
  margin: var(--gap-md) 0;
}

.report-title {
  text-align: center;
  font-size: var(--fs-section);
  font-weight: 700;
  margin-bottom: var(--gap-md);
  padding-bottom: var(--gap-sm);
  border-bottom: 2px solid var(--border);
}

.report-info {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--gap-sm);
  margin-bottom: var(--gap-md);
  font-size: var(--fs-body);
}

.report-info div {
  padding: var(--gap-xs) 0;
  border-bottom: 1px solid var(--border-light);
}

.report-label {
  color: var(--text-muted);
  margin-right: var(--gap-xs);
}

/* ============================================================
   图表
   ============================================================ */
.chart-container {
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  padding: var(--gap-md);
  margin: var(--gap-md) 0;
  border: 1px solid var(--border-light);
}

.chart-canvas {
  width: 100%;
  height: 300px;
  position: relative;
}

.chart-y-axis {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 30px;
  width: 50px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  font-size: var(--fs-micro);
  color: var(--text-muted);
  text-align: right;
  padding-right: var(--gap-xs);
}

.chart-x-axis {
  position: absolute;
  left: 50px;
  right: 0;
  bottom: 0;
  height: 30px;
  display: flex;
  justify-content: space-around;
  align-items: flex-end;
  font-size: var(--fs-micro);
  color: var(--text-muted);
}

.chart-area {
  position: absolute;
  left: 50px;
  top: 0;
  right: 0;
  bottom: 30px;
  border-left: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.chart-grid {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.chart-grid-line {
  border-top: 1px dashed var(--border-light);
}

.chart-line {
  position: absolute;
  inset: 0;
}

.chart-point {
  position: absolute;
  width: 10px;
  height: 10px;
  background: var(--primary);
  border: 2px solid white;
  border-radius: 50%;
  transform: translate(-50%, -50%);
  box-shadow: var(--shadow-sm);
}

.chart-path {
  fill: none;
  stroke: var(--primary);
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* ============================================================
   Tab 选项卡
   ============================================================ */
.tab-group {
  display: flex;
  border-bottom: 2px solid var(--border-light);
  margin-bottom: var(--gap-md);
  gap: var(--gap-xs);
  flex-wrap: wrap;
}

.tab-item {
  padding: 14px 24px;
  cursor: pointer;
  font-size: var(--fs-body);
  font-weight: 600;
  color: var(--text-secondary);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  transition: var(--transition-fast);
}

.tab-item:hover {
  color: var(--primary);
}

.tab-item.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

.tab-item:focus-visible {
  outline: 3px solid var(--primary-light);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

/* ============================================================
   小测验/选择题
   ============================================================ */
.quiz-option {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  padding: 16px var(--gap-lg);
  min-height: 54px;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: var(--fs-body);
  color: var(--text-secondary);
  transition: var(--transition-fast);
  margin-bottom: var(--gap-sm);
  background: var(--bg-card);
}

.quiz-option:hover {
  border-color: var(--primary-light);
  background: var(--bg-hover);
}

.quiz-option.selected {
  border-color: var(--primary);
  background: rgba(37, 99, 235, 0.06);
  color: var(--primary);
  font-weight: 600;
}

.quiz-option.correct {
  border-color: var(--success);
  background: rgba(34, 197, 94, 0.08);
  color: var(--success-dark);
  font-weight: 600;
}

.quiz-option.correct::after {
  content: "✓ 正确";
  margin-left: auto;
  font-size: var(--fs-label);
  font-weight: 700;
  color: var(--success);
}

.quiz-option.wrong {
  border-color: var(--danger);
  background: rgba(239, 68, 68, 0.08);
  color: var(--danger);
  font-weight: 600;
}

.quiz-option.wrong::after {
  content: "✗ 错误";
  margin-left: auto;
  font-size: var(--fs-label);
  font-weight: 700;
  color: var(--danger);
}

.quiz-option:focus-visible {
  outline: 3px solid var(--primary-light);
  outline-offset: 2px;
}

.quiz-option-letter {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--fs-label);
  flex-shrink: 0;
}

.quiz-option.selected .quiz-option-letter,
.quiz-option.correct .quiz-option-letter {
  background: var(--primary);
  color: var(--text-inverse);
}

.quiz-option.correct .quiz-option-letter {
  background: var(--success);
}

.quiz-option.wrong .quiz-option-letter {
  background: var(--danger);
  color: var(--text-inverse);
}

/* ============================================================
   Hero 学习目标区
   ============================================================ */
.hero-section {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--gap-lg);
  margin-bottom: var(--gap-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: linear-gradient(90deg, var(--primary) 0%, var(--accent) 100%);
}

.hero-title {
  font-size: var(--fs-module);
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: var(--gap-sm);
}

.hero-subtitle {
  font-size: var(--fs-body);
  color: var(--text-secondary);
  margin-bottom: var(--gap-md);
}

.hero-objectives {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--gap-md);
  margin-top: var(--gap-md);
}

.objective-card {
  padding: var(--gap-md) var(--gap-lg);
  border-radius: var(--radius-sm);
  border-left: 5px solid;
  background: var(--bg-page);
}

.objective-card.knowledge { border-left-color: var(--primary); }
.objective-card.skill { border-left-color: var(--accent); }
.objective-card.attitude { border-left-color: var(--success); }

.objective-card h4 {
  font-size: var(--fs-body);
  font-weight: 700;
  margin-bottom: var(--gap-xs);
  color: var(--text-primary);
}

.objective-card p {
  font-size: var(--fs-label);
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================================
   数据指标卡
   ============================================================ */
.data-metric {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--gap-md) var(--gap-lg);
  border-radius: var(--radius-sm);
  background: var(--bg-page);
  border: 1px solid var(--border-light);
  text-align: center;
}

.data-metric-label {
  font-size: var(--fs-label);
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: var(--gap-xs);
}

.data-metric-value {
  font-size: var(--fs-data);
  font-weight: 800;
  color: var(--primary);
  line-height: 1.2;
}

.data-metric-value.success { color: var(--success); }
.data-metric-value.warning { color: var(--warning-dark); }
.data-metric-value.danger { color: var(--danger); }

.data-metric-unit {
  font-size: var(--fs-label);
  color: var(--text-muted);
  margin-top: 4px;
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1200px) {
  .container {
    max-width: 100%;
  }
}

@media (max-width: 968px) {
  .main-layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }

  .header {
    padding: var(--gap-md);
  }

  .header h1 {
    font-size: 26px;
  }

  .container {
    padding: var(--gap-sm);
  }

  .card {
    padding: var(--gap-md);
  }

  .experiments-grid {
    grid-template-columns: 1fr;
  }

  .hero-objectives {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 600px) {
  :root {
    --fs-hero: 26px;
    --fs-module: 22px;
    --fs-section: 20px;
    --fs-body: 17px;
    --fs-btn: 17px;
    --fs-label: 16px;
  }

  .header {
    padding: var(--gap-md);
    border-radius: var(--radius-md);
  }

  .header h1 {
    font-size: 24px;
  }

  .btn {
    width: 100%;
    min-width: unset;
  }

  .btn-nav {
    flex-direction: column;
  }

  .btn-nav .btn {
    width: 100%;
  }

  .modal {
    padding: var(--gap-md);
    width: 95%;
  }

  .data-table {
    font-size: var(--fs-small);
  }

  .data-table th,
  .data-table td {
    padding: 10px var(--gap-sm);
  }

  .equipment-row {
    gap: var(--gap-md);
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .tab-item {
    padding: 10px var(--gap-sm);
    font-size: var(--fs-small);
  }
}

/* ============================================================
   浏览器缩放支持（125%, 150%）
   ============================================================ */
@media (min-resolution: 1.25dppx) {
  .container {
    max-width: 1200px;
  }
}

@media (min-resolution: 1.5dppx) {
  .container {
    max-width: 1100px;
  }

  .main-layout {
    grid-template-columns: 260px 1fr;
  }
}

/* ============================================================
   全屏模式
   ============================================================ */
:fullscreen .container {
  max-width: 100%;
  padding: var(--gap-sm);
}

:fullscreen .header {
  border-radius: var(--radius-md);
}

/* ============================================================
   工具类
   ============================================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.text-primary { color: var(--primary); }
.text-success { color: var(--success-dark); }
.text-warning { color: var(--warning-dark); }
.text-danger { color: var(--danger); }
.text-muted { color: var(--text-muted); }
.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.mt-sm { margin-top: var(--gap-sm); }
.mt-md { margin-top: var(--gap-md); }
.mt-lg { margin-top: var(--gap-lg); }
.mb-sm { margin-bottom: var(--gap-sm); }
.mb-md { margin-bottom: var(--gap-md); }
.mb-lg { margin-bottom: var(--gap-lg); }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.gap-sm { gap: var(--gap-sm); }
.gap-md { gap: var(--gap-md); }
.w-full { width: 100%; }