/* ===== 全局样式 ===== */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 90px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

::selection {
  background: var(--color-primary);
  color: #fff;
}

/* ===== 通用容器 ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: 96px 0;
  position: relative;
  overflow: hidden;
}

.section-alt {
  background-color: var(--color-bg-alt);
}

/* 交替 section 的点状纹理背景 */
.section-pattern::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: radial-gradient(var(--color-border) 1px, transparent 1px);
  background-size: 26px 26px;
  opacity: 0.5;
  pointer-events: none;
  mask-image: linear-gradient(180deg, transparent, black 15%, black 85%, transparent);
  -webkit-mask-image: linear-gradient(180deg, transparent, black 15%, black 85%, transparent);
}

.section .container {
  position: relative;
  z-index: 1;
}

/* ===== 标题样式（编号 + 主标题 + 英文小字） ===== */
.section-head {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  position: relative;
}

/* 大编号水印 */
.section-index {
  position: absolute;
  top: -44px;
  left: 50%;
  transform: translateX(-50%);
  font-family: var(--font-display);
  font-style: italic;
  font-size: clamp(4.5rem, 10vw, 7rem);
  font-weight: 800;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--color-border);
  user-select: none;
  pointer-events: none;
  z-index: 0;
}

.section-title {
  position: relative;
  z-index: 1;
  font-family: var(--font-display);
  font-size: clamp(2rem, 4.5vw, 2.75rem);
  font-weight: 800;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.section-title span {
  color: var(--color-primary);
  position: relative;
  white-space: nowrap;
}

/* 高亮词底部手绘感色块 */
.section-title span::after {
  content: '';
  position: absolute;
  left: -2%;
  right: -2%;
  bottom: 4px;
  height: 10px;
  background: linear-gradient(90deg, var(--color-secondary-light), transparent);
  opacity: 0.6;
  border-radius: 4px;
  z-index: -1;
  transform: skewX(-8deg);
}

.section-subtitle {
  position: relative;
  z-index: 1;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-family: var(--font-display);
  letter-spacing: 0.22em;
  text-transform: uppercase;
}

.section-subtitle::after {
  content: '';
  display: block;
  width: 44px;
  height: 3px;
  margin: var(--spacing-md) auto 0;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
}

/* 空状态提示 */
.empty-tip {
  text-align: center;
  color: var(--color-text-muted);
  padding: var(--spacing-2xl);
  font-size: 0.95rem;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: 14px 30px;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 0.95rem;
  transition: all var(--transition-normal);
  cursor: pointer;
  border: none;
  font-family: inherit;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  box-shadow: 0 4px 15px rgba(255, 138, 158, 0.35);
  position: relative;
  overflow: hidden;
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.35), transparent);
  transition: left 0.5s ease;
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(255, 138, 158, 0.45);
  color: white;
}

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

.btn-secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-3px);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.1);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* ===== 标签 ===== */
.tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  background: var(--color-secondary-light);
  color: var(--color-secondary-dark);
  font-size: 0.8rem;
  font-weight: 500;
  margin: 2px;
}

[data-theme="dark"] .tag {
  background: rgba(91, 184, 175, 0.15);
  color: var(--color-secondary-light);
}

/* ===== 卡片 ===== */
.card {
  background: var(--color-card);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}

/* ===== 键盘焦点可见性 ===== */
a:focus-visible,
button:focus-visible,
[tabindex="0"]:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .section {
    padding: 64px 0;
  }
  .container {
    padding: 0 var(--spacing-md);
  }
  .section-index {
    top: -30px;
    font-size: 4rem;
  }
}

/* ===== 降低动效偏好 ===== */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}