/* ====================================================================
   速云梯 (suyunti.help) — 样式设计系统
   主题：夏日祭夜市 · 水彩晕染 · 卡牌收集 · 220° 类比色相
   规范：BEM 命名体系 · 原生纯净 CSS · 无外部依赖 · 响应式优先
   ==================================================================== */

:root {
  /* 基础色彩：220° 类比夏夜色彩体系 */
  --color-bg-base: #0b1120;
  --color-bg-surface: #0f172a;
  --color-bg-card: rgba(15, 23, 42, 0.85);
  --color-bg-card-hover: rgba(30, 41, 59, 0.9);
  
  --color-primary: #0284c7;
  --color-primary-light: #38bdf8;
  --color-primary-glow: rgba(56, 189, 248, 0.25);
  
  --color-indigo: #4338ca;
  --color-indigo-light: #6366f1;
  --color-twilight: #1e3a8a;
  
  --color-accent-gold: #f59e0b;
  --color-accent-amber: #fbbf24;
  --color-accent-lantern: #ea580c;
  --color-accent-glow: rgba(245, 158, 11, 0.2);

  --color-text-main: #f8fafc;
  --color-text-muted: #94a3b8;
  --color-text-subtle: #64748b;
  
  --color-border: rgba(56, 189, 248, 0.18);
  --color-border-card: rgba(56, 189, 248, 0.25);
  --color-border-gold: rgba(245, 158, 11, 0.4);

  /* 排版系统 */
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  
  /* 阴影与光晕 */
  --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 25px rgba(56, 189, 248, 0.2);
  --shadow-gold: 0 0 25px rgba(245, 158, 11, 0.25);
  
  /* 布局与圆角 */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;
  --container-max: 1200px;
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--color-bg-base);
  color: var(--color-text-main);
  scroll-behavior: smooth;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  background-image: 
    radial-gradient(circle at 15% 20%, rgba(2, 132, 199, 0.12) 0%, transparent 40%),
    radial-gradient(circle at 85% 30%, rgba(67, 56, 202, 0.15) 0%, transparent 45%),
    radial-gradient(circle at 50% 75%, rgba(245, 158, 11, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 75% 90%, rgba(2, 132, 199, 0.1) 0%, transparent 40%);
  background-attachment: fixed;
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  display: block;
  max-width: 100%;
}

ul, ol {
  list-style: none;
}

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

/* 容器定义 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* 模块通用样式 */
.section-wrapper {
  padding: 5rem 0;
  position: relative;
}

.section-wrapper--alt {
  background: rgba(15, 23, 42, 0.5);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 3.5rem;
}

.section-header__badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--color-accent-amber);
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid var(--color-border-gold);
  padding: 0.25rem 0.85rem;
  border-radius: var(--radius-full);
  margin-bottom: 1rem;
}

.section-header__title {
  font-size: 2.15rem;
  font-weight: 700;
  color: var(--color-text-main);
  line-height: 1.3;
  margin-bottom: 1rem;
}

.section-header__desc {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* 按钮规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.75rem 1.6rem;
  border-radius: var(--radius-md);
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
  text-align: center;
  white-space: nowrap;
}

.btn--primary {
  background: linear-gradient(135deg, #0284c7 0%, #0369a1 100%);
  color: #ffffff;
  box-shadow: 0 4px 15px rgba(2, 132, 199, 0.35);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.btn--primary:hover {
  background: linear-gradient(135deg, #0ea5e9 0%, #0284c7 100%);
  box-shadow: 0 6px 20px rgba(2, 132, 199, 0.5);
  transform: translateY(-2px);
}

.btn--gold {
  background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
  color: #0b1120;
  font-weight: 700;
  box-shadow: 0 4px 16px rgba(245, 158, 11, 0.35);
  border: 1px solid rgba(251, 191, 36, 0.5);
}

.btn--gold:hover {
  background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
  box-shadow: 0 6px 22px rgba(245, 158, 11, 0.5);
  transform: translateY(-2px);
}

.btn--secondary {
  background: rgba(30, 41, 59, 0.7);
  color: var(--color-text-main);
  border: 1px solid var(--color-border);
}

.btn--secondary:hover {
  background: rgba(51, 65, 85, 0.85);
  border-color: var(--color-primary-light);
  transform: translateY(-2px);
}

.btn--large {
  padding: 0.9rem 2.2rem;
  font-size: 1.05rem;
}

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

/* ====================================================================
   组件：顶部导航栏 (Header)
   ==================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(11, 17, 32, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: padding 0.3s ease, background 0.3s ease, box-shadow 0.3s ease;
  padding: 1.1rem 0;
}

.site-header--compact {
  padding: 0.65rem 0;
  background: rgba(11, 17, 32, 0.95);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.site-header__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-header__brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-main);
}

.site-header__brand-icon {
  width: 32px;
  height: 32px;
  display: inline-block;
}

.site-header__brand-sub {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-accent-amber);
  margin-left: 0.35rem;
  padding: 0.1rem 0.45rem;
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid var(--color-border-gold);
  border-radius: var(--radius-sm);
}

.site-header__nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.site-header__link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color 0.2s ease;
}

.site-header__link:hover {
  color: var(--color-primary-light);
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.site-header__toggle {
  display: none;
  padding: 0.5rem;
  color: var(--color-text-main);
}

/* ====================================================================
   组件：Hero 英雄区
   ==================================================================== */
.hero-section {
  padding: 5.5rem 0 4rem;
  position: relative;
  overflow: hidden;
}

.hero-section__container {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 3.5rem;
  align-items: center;
}

.hero-section__badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-primary-light);
  background: rgba(2, 132, 199, 0.15);
  border: 1px solid rgba(56, 189, 248, 0.3);
  padding: 0.35rem 0.95rem;
  border-radius: var(--radius-full);
  margin-bottom: 1.5rem;
}

.hero-section__title {
  font-size: 2.75rem;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 1.5rem;
  letter-spacing: -0.02em;
}

.hero-section__title-highlight {
  color: transparent;
  background: linear-gradient(135deg, #38bdf8 0%, #fbbf24 100%);
  -webkit-background-clip: text;
  background-clip: text;
}

.hero-section__subtitle {
  font-size: 1.12rem;
  color: var(--color-text-muted);
  line-height: 1.75;
  margin-bottom: 2.25rem;
}

.hero-section__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 3rem;
}

.hero-section__stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--color-border);
}

.hero-section__stat-num {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-main);
  font-family: var(--font-mono);
}

.hero-section__stat-num--accent {
  color: var(--color-accent-amber);
}

.hero-section__stat-label {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-top: 0.2rem;
}

/* 吉祥物展台卡片 */
.mascot-card {
  position: relative;
  background: linear-gradient(145deg, rgba(15, 23, 42, 0.85) 0%, rgba(30, 41, 59, 0.65) 100%);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-card), var(--shadow-glow);
  text-align: center;
}

.mascot-card__badge {
  position: absolute;
  top: 1rem;
  left: 1rem;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--color-accent-amber);
  background: rgba(245, 158, 11, 0.15);
  border: 1px solid var(--color-border-gold);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  letter-spacing: 0.05em;
}

.mascot-card__avatar {
  width: 220px;
  height: 220px;
  margin: 0.5rem auto 1.5rem;
}

.mascot-card__bubble {
  background: rgba(2, 132, 199, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.25);
  border-radius: var(--radius-md);
  padding: 1rem;
  font-size: 0.9rem;
  color: #e0f2fe;
  line-height: 1.6;
}

.mascot-card__status {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.82rem;
  color: #4ade80;
  margin-top: 1rem;
}

.mascot-card__status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: #4ade80;
  box-shadow: 0 0 8px #4ade80;
}

/* ====================================================================
   特性卡片 · 卡牌收集样式 (Card Collection & Tilt)
   ==================================================================== */
.card {
  position: relative;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  padding: 2rem;
  box-shadow: var(--shadow-card);
  transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.card--hover-tilt:hover {
  transform: translateY(-4px) rotate(-0.5deg);
  border-color: rgba(56, 189, 248, 0.45);
  box-shadow: 0 16px 35px -8px rgba(2, 132, 199, 0.25);
}

.card__corner-no {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-accent-amber);
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid var(--color-border-gold);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  letter-spacing: 0.05em;
}

/* ====================================================================
   3D 翻转卡片 (Flip Card)
   ==================================================================== */
.flip-card {
  perspective: 1200px;
  min-height: 280px;
}

.flip-card__inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
  transform-style: preserve-3d;
}

.flip-card:hover .flip-card__inner,
.flip-card.is-flipped .flip-card__inner {
  transform: rotateY(180deg);
}

.flip-card__front,
.flip-card__back {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: var(--radius-md);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.flip-card__front {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  box-shadow: var(--shadow-card);
}

.flip-card__back {
  background: linear-gradient(145deg, #1e293b 0%, #0f172a 100%);
  border: 1px solid var(--color-primary-light);
  box-shadow: var(--shadow-glow);
  transform: rotateY(180deg);
}

/* ====================================================================
   组件：特性模块 (图文左右交错)
   ==================================================================== */
.feature-stagger {
  display: flex;
  flex-direction: column;
  gap: 3.5rem;
}

.feature-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3.5rem;
  align-items: center;
}

.feature-row--reverse {
  direction: rtl;
}

.feature-row--reverse > * {
  direction: ltr;
}

.feature-row__content {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.feature-row__tag {
  align-self: flex-start;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-primary-light);
  background: rgba(2, 132, 199, 0.15);
  border: 1px solid rgba(56, 189, 248, 0.25);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-sm);
  letter-spacing: 0.05em;
}

.feature-row__title {
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--color-text-main);
  line-height: 1.3;
}

.feature-row__desc {
  font-size: 1rem;
  color: var(--color-text-muted);
  line-height: 1.75;
}

.feature-row__list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.feature-row__item {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  font-size: 0.95rem;
  color: #cbd5e1;
}

.feature-row__item-icon {
  color: #38bdf8;
  font-weight: 700;
}

/* 特性图文的卡片视觉区 */
.feature-row__visual {
  height: 100%;
}

.card-spec {
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: linear-gradient(135deg, rgba(15, 23, 42, 0.9) 0%, rgba(30, 41, 59, 0.7) 100%);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  padding: 2.25rem;
  box-shadow: var(--shadow-card);
  position: relative;
}

.card-spec__badge {
  font-size: 0.75rem;
  color: var(--color-accent-amber);
  font-family: var(--font-mono);
  margin-bottom: 1rem;
}

.card-spec__highlight {
  font-size: 1.35rem;
  font-weight: 700;
  color: #e0f2fe;
  margin-bottom: 0.75rem;
}

.card-spec__note {
  font-size: 0.92rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ====================================================================
   组件：AI 支持模块
   ==================================================================== */
.ai-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.ai-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  padding: 2rem;
  transition: all 0.25s ease;
  position: relative;
}

.ai-card:hover {
  transform: translateY(-4px);
  border-color: rgba(56, 189, 248, 0.45);
  box-shadow: var(--shadow-glow);
}

.ai-card__header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.ai-card__icon-box {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: rgba(2, 132, 199, 0.15);
  border: 1px solid rgba(56, 189, 248, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #38bdf8;
}

.ai-card__title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-text-main);
}

.ai-card__desc {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 1.25rem;
}

.ai-card__tag {
  display: inline-block;
  font-size: 0.78rem;
  color: var(--color-accent-amber);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid var(--color-border-gold);
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-sm);
}

/* ====================================================================
   组件：流媒体支持模块
   ==================================================================== */
.stream-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.stream-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  padding: 1.75rem 1.5rem;
  text-align: center;
  transition: all 0.25s ease;
}

.stream-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-primary-light);
  box-shadow: var(--shadow-glow);
}

.stream-card__logo {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.stream-card__logo--netflix { color: #e50914; }
.stream-card__logo--disney { color: #38bdf8; }
.stream-card__logo--youtube { color: #ff0000; }
.stream-card__logo--spotify { color: #1db954; }

.stream-card__title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.stream-card__desc {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ====================================================================
   组件：定价卡片 (3档并列卡片，推荐中档)
   ==================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  align-items: stretch;
}

.pricing-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: all 0.3s ease;
}

.pricing-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-card);
}

.pricing-card--popular {
  background: linear-gradient(145deg, rgba(15, 23, 42, 0.95) 0%, rgba(30, 58, 138, 0.45) 100%);
  border: 2px solid var(--color-accent-amber);
  box-shadow: var(--shadow-card), var(--shadow-gold);
  transform: scale(1.03);
}

.pricing-card--popular:hover {
  transform: scale(1.03) translateY(-6px);
}

.pricing-card__crown {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, #f59e0b 0%, #ea580c 100%);
  color: #0b1120;
  font-size: 0.8rem;
  font-weight: 800;
  padding: 0.3rem 1.25rem;
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
  white-space: nowrap;
}

.pricing-card__name {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.pricing-card__desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  min-height: 42px;
  margin-bottom: 1.5rem;
}

.pricing-card__price-box {
  display: flex;
  align-items: baseline;
  gap: 0.35rem;
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.pricing-card__currency {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-accent-amber);
}

.pricing-card__amount {
  font-size: 2.75rem;
  font-weight: 800;
  color: var(--color-text-main);
  font-family: var(--font-mono);
  line-height: 1;
}

.pricing-card__period {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.pricing-card__features {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  margin-bottom: 2.5rem;
  flex-grow: 1;
}

.pricing-card__feature-item {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  font-size: 0.92rem;
  color: #cbd5e1;
}

.pricing-card__feature-icon {
  color: #38bdf8;
  font-weight: 700;
}

/* ====================================================================
   组件：FAQ 双列手风琴
   ==================================================================== */
.faq-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  align-items: start;
}

.faq-item {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.faq-item:hover {
  border-color: rgba(56, 189, 248, 0.4);
}

.faq-item__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.35rem 1.5rem;
  text-align: left;
  gap: 1rem;
}

.faq-item__title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text-main);
  line-height: 1.45;
}

.faq-item__icon {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: rgba(2, 132, 199, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #38bdf8;
  flex-shrink: 0;
  transition: transform 0.25s ease;
}

.faq-item__trigger[aria-expanded="true"] .faq-item__icon {
  transform: rotate(180deg);
  background: rgba(245, 158, 11, 0.2);
  color: var(--color-accent-amber);
}

.faq-item__content {
  display: none;
  padding: 0 1.5rem 1.35rem;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.75;
}

.faq-item__content[aria-hidden="false"] {
  display: block;
}

/* ====================================================================
   组件：Final CTA 底部召回卡片
   ==================================================================== */
.final-cta {
  padding: 5rem 0;
}

.final-cta__box {
  background: radial-gradient(circle at 50% 30%, rgba(2, 132, 199, 0.3) 0%, rgba(15, 23, 42, 0.95) 75%);
  border: 1px solid var(--color-primary-light);
  border-radius: var(--radius-lg);
  padding: 4.5rem 2rem;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.final-cta__title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-text-main);
  margin-bottom: 1rem;
}

.final-cta__desc {
  font-size: 1.1rem;
  color: #cbd5e1;
  max-width: 620px;
  margin: 0 auto 2.25rem;
  line-height: 1.7;
}

/* ====================================================================
   组件：文章列表页 (guides.html) 与 单篇详情页 (Article)
   ==================================================================== */
.breadcrumb {
  padding: 1.5rem 0;
  font-size: 0.88rem;
  color: var(--color-text-subtle);
}

.breadcrumb__list {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.breadcrumb__item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.breadcrumb__link {
  color: var(--color-text-muted);
  transition: color 0.2s ease;
}

.breadcrumb__link:hover {
  color: var(--color-primary-light);
}

.breadcrumb__separator {
  color: var(--color-text-subtle);
}

/* 指南卡片网格 */
.guides-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.guides-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all 0.25s ease;
}

.guides-card:hover {
  transform: translateY(-4px);
  border-color: rgba(56, 189, 248, 0.45);
  box-shadow: var(--shadow-card);
}

.guides-card__meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.8rem;
  color: var(--color-text-subtle);
  margin-bottom: 1rem;
}

.guides-card__tag {
  color: var(--color-accent-amber);
  background: rgba(245, 158, 11, 0.1);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.guides-card__title {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 0.85rem;
}

.guides-card__excerpt {
  font-size: 0.92rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.guides-card__link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-primary-light);
}

.guides-card__link:hover {
  color: var(--color-accent-amber);
}

/* 文章详情页结构 */
.article-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 3.5rem;
  padding: 2rem 0 5rem;
  align-items: start;
}

.article-sidebar {
  position: sticky;
  top: 5.5rem;
}

.article-toc {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  padding: 1.5rem;
}

.article-toc__title {
  font-size: 0.95rem;
  font-weight: 700;
  color: #e0f2fe;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.article-toc__list {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.article-toc__link {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.4;
  transition: color 0.2s ease;
}

.article-toc__link:hover {
  color: var(--color-primary-light);
}

.article-body {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-card);
  border-radius: var(--radius-md);
  padding: 3rem 2.5rem;
  box-shadow: var(--shadow-card);
}

.article-body__header {
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--color-border);
}

.article-body__tag {
  display: inline-block;
  font-size: 0.8rem;
  color: var(--color-accent-amber);
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid var(--color-border-gold);
  padding: 0.2rem 0.65rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}

.article-body__h1 {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 1rem;
}

.article-body__meta {
  display: flex;
  gap: 1.5rem;
  font-size: 0.85rem;
  color: var(--color-text-subtle);
}

.article-body__lead {
  font-size: 1.12rem;
  line-height: 1.8;
  color: #cbd5e1;
  background: rgba(2, 132, 199, 0.08);
  border-left: 4px solid var(--color-primary-light);
  padding: 1.25rem 1.5rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-bottom: 2.5rem;
}

.article-body h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: #f8fafc;
  margin: 2.5rem 0 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.07);
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: #e2e8f0;
  margin: 1.75rem 0 0.85rem;
}

.article-body p {
  font-size: 1rem;
  line-height: 1.8;
  color: #cbd5e1;
  margin-bottom: 1.25rem;
}

.article-body ul, .article-body ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.article-body ul {
  list-style-type: disc;
}

.article-body ol {
  list-style-type: decimal;
}

.article-body li {
  font-size: 0.98rem;
  line-height: 1.75;
  color: #cbd5e1;
  margin-bottom: 0.5rem;
}

.article-body blockquote {
  border-left: 3px solid var(--color-accent-amber);
  background: rgba(245, 158, 11, 0.06);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  font-size: 0.95rem;
  color: #e2e8f0;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.75rem 0;
}

.article-body th, .article-body td {
  padding: 0.85rem 1rem;
  border: 1px solid var(--color-border);
  text-align: left;
  font-size: 0.92rem;
}

.article-body th {
  background: rgba(15, 23, 42, 0.9);
  color: #f8fafc;
  font-weight: 700;
}

.article-body tr:nth-child(even) {
  background: rgba(255, 255, 255, 0.02);
}

.article-cta-box {
  background: linear-gradient(135deg, rgba(2, 132, 199, 0.2) 0%, rgba(15, 23, 42, 0.9) 100%);
  border: 1px solid var(--color-primary-light);
  border-radius: var(--radius-md);
  padding: 2.5rem 2rem;
  text-align: center;
  margin: 3.5rem 0 2rem;
}

.article-cta-box__title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.article-cta-box__desc {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  max-width: 520px;
  margin: 0 auto 1.5rem;
}

/* ====================================================================
   组件：页脚 (Footer)
   ==================================================================== */
.site-footer {
  background: #070c18;
  border-top: 1px solid var(--color-border);
  padding: 4rem 0 2.5rem;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.site-footer__container {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.site-footer__brand-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-text-main);
  margin-bottom: 0.75rem;
}

.site-footer__brand-desc {
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--color-text-muted);
  max-width: 380px;
}

.site-footer__col-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text-main);
  margin-bottom: 1rem;
}

.site-footer__links {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.site-footer__link {
  color: var(--color-text-muted);
  transition: color 0.2s ease;
}

.site-footer__link:hover {
  color: var(--color-primary-light);
}

.site-footer__bottom {
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--color-text-subtle);
}

.site-footer__disclosure {
  color: #94a3b8;
  font-size: 0.85rem;
}

/* ====================================================================
   移动端底吸 CTA 与 返回顶部
   ==================================================================== */
.mobile-sticky-cta {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 99;
  background: rgba(11, 17, 32, 0.95);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--color-border);
  padding: 0.75rem 1.25rem;
  box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.5);
}

.mobile-sticky-cta__btn {
  width: 100%;
}

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 90;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(15, 23, 42, 0.9);
  border: 1px solid var(--color-border);
  color: var(--color-primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.25s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4);
}

.back-to-top--visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: var(--color-primary);
  color: #ffffff;
  transform: translateY(-3px);
}

/* 移动端抽屉菜单 */
.mobile-drawer {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: none;
}

.mobile-drawer--open {
  display: block;
}

.mobile-drawer__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(4px);
}

.mobile-drawer__content {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 280px;
  background: #0b1120;
  border-left: 1px solid var(--color-border);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  box-shadow: -5px 0 25px rgba(0, 0, 0, 0.6);
}

.mobile-drawer__close {
  align-self: flex-end;
  color: var(--color-text-muted);
  font-size: 1.5rem;
}

.mobile-drawer__nav {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.mobile-drawer__link {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text-main);
}

/* ====================================================================
   响应式断点 (Media Queries)
   ==================================================================== */
@media (max-width: 1024px) {
  .hero-section__container {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  .hero-section__stats {
    max-width: 500px;
  }
  .ai-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .stream-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 480px;
    margin: 0 auto;
  }
  .pricing-card--popular {
    transform: none;
  }
  .pricing-card--popular:hover {
    transform: translateY(-6px);
  }
  .guides-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .article-layout {
    grid-template-columns: 1fr;
  }
  .article-sidebar {
    display: none;
  }
}

@media (max-width: 768px) {
  .site-header__nav, .site-header__actions .btn--primary {
    display: none;
  }
  .site-header__toggle {
    display: block;
  }
  .hero-section__title {
    font-size: 2.1rem;
  }
  .feature-row, .feature-row--reverse {
    grid-template-columns: 1fr;
    gap: 2rem;
    direction: ltr;
  }
  .ai-grid {
    grid-template-columns: 1fr;
  }
  .faq-grid {
    grid-template-columns: 1fr;
  }
  .guides-grid {
    grid-template-columns: 1fr;
  }
  .site-footer__container {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  .mobile-sticky-cta {
    display: block;
  }
  body {
    padding-bottom: 4.5rem; /* 为底部吸底按钮留出间距 */
  }
}