/* ============================================
   烫伤模拟器 — 通用样式 (植物清新风)
   ============================================ */

/* --- CSS 自定义属性 (主题色) --- */
:root {
  --color-bg: #1a0a2e;
  --color-bg-card: rgba(30, 10, 50, 0.85);
  --color-primary: #c77dff;
  --color-accent: #ff6ec7;
  --color-text: #f0e6ff;
  --color-text-dim: #c4a0e8;
  --color-border: rgba(199, 125, 255, 0.3);
  --color-glow: rgba(199, 125, 255, 0.2);
  --color-success: #c77dff;
  --color-danger: #ff6b6b;
  --color-warning: #ffd93d;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow-card: 0 4px 20px rgba(199, 125, 255, 0.15);
  --font-stack: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
}

/* --- 全局重置 --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-stack);
  background: linear-gradient(135deg, #1a0a2e 0%, #2d1b4e 25%, #4a1a5e 50%, #2d1b4e 75%, #1a0a2e 100%);
  color: var(--color-text);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
}

/* --- 粒子极光背景 --- */
body::before {
  content: '';
  position: fixed;
  top: 0; left: 0; width: 100%; height: 100%;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 60% at 20% 30%, rgba(199,125,255,0.12) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 80% 70%, rgba(255,110,199,0.1) 0%, transparent 50%),
    radial-gradient(ellipse 70% 40% at 50% 20%, rgba(255,217,61,0.06) 0%, transparent 50%);
  animation: auroraDrift 12s ease-in-out infinite alternate;
}

@keyframes auroraDrift {
  0% { transform: translate(0, 0) scale(1); opacity: 0.6; }
  50% { transform: translate(2%, 1%) scale(1.05); opacity: 0.8; }
  100% { transform: translate(-1%, -1%) scale(0.95); opacity: 0.6; }
}

/* --- 星星粒子 --- */
body::after {
  content: '';
  position: fixed;
  top: 0; left: 0; width: 100%; height: 100%;
  z-index: 0;
  pointer-events: none;
  background-image:
    radial-gradient(2px 2px at 10% 15%, rgba(255,255,255,0.8) 0%, transparent 100%),
    radial-gradient(2px 2px at 25% 45%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 40% 10%, rgba(255,255,255,0.9) 0%, transparent 100%),
    radial-gradient(2px 2px at 55% 70%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 70% 25%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(2px 2px at 85% 55%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 15% 80%, rgba(255,255,255,0.8) 0%, transparent 100%),
    radial-gradient(2px 2px at 90% 15%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 35% 90%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(2px 2px at 60% 40%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 5% 55%, rgba(255,255,255,0.9) 0%, transparent 100%),
    radial-gradient(2px 2px at 75% 85%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 45% 35%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(2px 2px at 95% 45%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 20% 65%, rgba(255,255,255,0.8) 0%, transparent 100%);
  animation: twinkle 4s ease-in-out infinite alternate;
}

@keyframes twinkle {
  0% { opacity: 0.5; }
  50% { opacity: 0.8; }
  100% { opacity: 0.5; }
}

/* --- 布局容器 --- */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px;
  position: relative;
  z-index: 1;
}

/* --- 渐变标题 --- */
.gradient-title {
  font-size: 2.2rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 8px;
}

.subtitle {
  color: var(--color-text-dim);
  font-size: 1rem;
  margin-bottom: 24px;
}

/* --- 导航栏 --- */
.top-nav {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 12px 0;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.top-nav a {
  color: var(--color-text-dim);
  text-decoration: none;
  font-size: 0.9rem;
  padding: 6px 14px;
  border-radius: 20px;
  transition: all 0.3s ease;
  border: 1px solid transparent;
}

.top-nav a:hover {
  color: var(--color-text);
  background: rgba(124, 92, 252, 0.15);
  border-color: var(--color-border);
}

.top-nav .nav-home {
  font-weight: 700;
  color: var(--color-primary);
  border: none;
  background: none;
}

/* --- 卡片 --- */
.card {
  background: rgba(30, 10, 50, 0.75);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(12px);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 28px rgba(199, 125, 255, 0.2);
}

/* --- 首页导航卡片网格 --- */
.nav-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
  margin-top: 20px;
}

.nav-card {
  background: rgba(30, 10, 50, 0.75);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px 24px;
  text-align: center;
  cursor: pointer;
  text-decoration: none;
  color: var(--color-text);
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  backdrop-filter: blur(12px);
}

.nav-card:hover {
  transform: translateY(-6px) scale(1.02);
  border-color: var(--color-primary);
  box-shadow: 0 4px 24px var(--color-glow);
}

.nav-card .icon {
  font-size: 3rem;
  line-height: 1;
}

.nav-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
}

.nav-card p {
  font-size: 0.85rem;
  color: var(--color-text-dim);
  line-height: 1.5;
}

/* --- 按钮 --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  font-family: var(--font-stack);
  cursor: pointer;
  border: none;
  transition: all 0.25s ease;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, #c77dff, #ff6ec7);
  color: #fff;
  box-shadow: 0 4px 16px rgba(199, 125, 255, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(199, 125, 255, 0.4);
}

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

.btn-secondary {
  background: rgba(67, 160, 71, 0.1);
  color: var(--color-primary);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: rgba(67, 160, 71, 0.18);
}

.btn-success {
  background: linear-gradient(135deg, var(--color-success), #6ee7b7);
  color: #0b0a1a;
}

.btn-danger {
  background: linear-gradient(135deg, var(--color-danger), #fca5a5);
  color: #0b0a1a;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* --- 选项按钮 (选择题用) --- */
.option-btn {
  display: block;
  width: 100%;
  text-align: left;
  padding: 14px 20px;
  margin-bottom: 10px;
  background: rgba(199, 125, 255, 0.08);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-size: 1rem;
  font-family: var(--font-stack);
  cursor: pointer;
  transition: all 0.25s ease;
}

.option-btn:hover {
  border-color: var(--color-primary);
  background: rgba(199, 125, 255, 0.15);
}

.option-btn.selected {
  border-color: var(--color-primary);
  background: rgba(199, 125, 255, 0.2);
}

.option-btn.correct {
  border-color: var(--color-success);
  background: rgba(199, 125, 255, 0.2);
}

.option-btn.wrong {
  border-color: var(--color-danger);
  background: rgba(255, 107, 107, 0.15);
}

/* --- 进度条 --- */
.progress-bar {
  width: 100%;
  height: 8px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  overflow: hidden;
  margin: 16px 0;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  border-radius: 4px;
  transition: width 0.5s ease;
}

/* --- 反馈消息 --- */
.feedback-box {
  padding: 16px 20px;
  border-radius: var(--radius-sm);
  margin: 16px 0;
  font-weight: 600;
  animation: fadeInUp 0.4s ease;
}

.feedback-box.success {
  background: rgba(52, 211, 153, 0.15);
  border: 1px solid var(--color-success);
  color: var(--color-success);
}

.feedback-box.error {
  background: rgba(251, 113, 133, 0.15);
  border: 1px solid var(--color-danger);
  color: var(--color-danger);
}

.feedback-box.info {
  background: rgba(67, 160, 71, 0.1);
  border: 1px solid var(--color-primary);
  color: var(--color-primary);
}

/* --- 动画 --- */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.fade-in {
  animation: fadeIn 0.6s ease;
}

/* --- 列表样式 (指南页用) --- */
.styled-list {
  list-style: none;
  padding: 0;
}

.styled-list li {
  padding: 12px 16px;
  margin-bottom: 8px;
  background: rgba(67, 160, 71, 0.04);
  border-left: 3px solid var(--color-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  line-height: 1.6;
}

.styled-list li strong {
  color: var(--color-accent);
}

/* --- 步骤编号 (指南页用) --- */
.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), #81c784);
  color: #fff;
  font-weight: 700;
  font-size: 0.9rem;
  margin-right: 12px;
  flex-shrink: 0;
}

/* --- 响应式 --- */
@media (max-width: 640px) {
  .container {
    padding: 12px;
  }

  .gradient-title {
    font-size: 1.6rem;
  }

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

  .top-nav {
    gap: 8px;
  }

  .top-nav a {
    font-size: 0.8rem;
    padding: 4px 10px;
  }

  .card {
    padding: 16px;
  }

  .btn {
    padding: 10px 20px;
    font-size: 0.9rem;
  }
}