/* HOAI 下载页 — 设计系统：单色品牌 + 蓝紫强调 */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;600;700&family=Plus+Jakarta+Sans:wght@400;500;600;700&display=swap');

:root {
  --color-primary: #18181b;
  --color-secondary: #3f3f46;
  --color-cta: #2563eb;
  --color-cta-hover: #1d4ed8;
  --color-accent: #6366f1;
  --color-success: #10b981;
  --color-bg: #fafaf9;
  --color-surface: #ffffff;
  --color-text: #09090b;
  --color-muted: #52525b;
  --color-border: #e4e4e7;
  --font-heading: 'Plus Jakarta Sans', 'Noto Sans SC', sans-serif;
  --font-body: 'Noto Sans SC', 'Plus Jakarta Sans', sans-serif;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.1);
  --radius: 12px;
  --radius-lg: 16px;
  --transition: 200ms ease;
  --nav-height: 72px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

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

a:hover {
  color: var(--color-cta-hover);
}

.container {
  width: min(1120px, 100% - 2rem);
  margin-inline: auto;
}

/* Nav */
.site-nav {
  position: fixed;
  top: var(--space-md);
  left: var(--space-md);
  right: var(--space-md);
  z-index: 100;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-lg);
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text);
  font-weight: 600;
  font-family: var(--font-heading);
}

.nav-brand img {
  width: 40px;
  height: 40px;
  object-fit: contain;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--color-muted);
  font-size: 0.9375rem;
  font-weight: 500;
}

.nav-links a:hover {
  color: var(--color-text);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.5rem 1rem;
  background: var(--color-primary);
  color: #fff !important;
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), opacity var(--transition);
}

.nav-cta:hover {
  background: #27272a;
  color: #fff !important;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  padding: var(--space-sm);
  cursor: pointer;
}

/* Hero */
.hero {
  padding: calc(var(--nav-height) + var(--space-3xl) + var(--space-xl)) 0 var(--space-3xl);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.75rem;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-muted);
  margin-bottom: var(--space-md);
}

.hero-badge svg {
  color: #f59e0b;
}

.hero h1 {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  line-height: 1.2;
  margin: 0 0 var(--space-md);
  letter-spacing: -0.02em;
}

.hero-sub {
  font-size: 1.125rem;
  color: var(--color-muted);
  margin: 0 0 var(--space-xl);
  max-width: 32rem;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
  font-size: 0.875rem;
  color: var(--color-muted);
}

.hero-meta span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

/* 下载区块 */
.download-block {
  margin-bottom: var(--space-xl);
}

.mirror-sync-note {
  margin: 0 0 var(--space-md);
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.75);
  text-align: center;
}

.mirror-panel {
  margin-bottom: var(--space-lg);
}

.mirror-panel-head {
  margin-bottom: var(--space-md);
}

.mirror-panel-title {
  margin: 0 0 var(--space-xs);
  font-family: var(--font-heading);
  font-size: 1.125rem;
  font-weight: 600;
}

.mirror-panel-desc {
  margin: 0;
  font-size: 0.875rem;
  color: var(--color-muted);
}

.mirror-switch {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-sm);
  padding: 4px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.mirror-tab {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.35rem;
  padding: var(--space-md);
  background: transparent;
  border: 2px solid transparent;
  border-radius: 10px;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-body);
  color: var(--color-muted);
  transition: border-color var(--transition), background var(--transition), color var(--transition);
  position: relative;
}

.mirror-tab:hover {
  background: #f4f4f5;
  color: var(--color-text);
}

.mirror-tab:focus-visible {
  outline: 2px solid var(--color-cta);
  outline-offset: 2px;
}

.mirror-tab.is-active {
  background: #fff;
  border-color: var(--color-cta);
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
}

.mirror-tab-icon {
  color: var(--color-cta);
}

.mirror-tab-text strong {
  display: block;
  font-size: 0.9375rem;
  color: var(--color-text);
}

.mirror-tab-text small {
  font-size: 0.75rem;
  color: var(--color-muted);
}

.mirror-tab-badge {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 0.1rem 0.45rem;
  font-size: 0.6875rem;
  font-weight: 600;
  color: #fff;
  background: var(--color-cta);
  border-radius: 4px;
}

.mirror-hint {
  margin: var(--space-md) 0;
  padding: var(--space-sm) var(--space-md);
  font-size: 0.8125rem;
  color: var(--color-muted);
  background: #f4f4f5;
  border-radius: 8px;
  border-left: 3px solid var(--color-cta);
}

.mirror-hint strong {
  color: var(--color-text);
}

.mirror-details {
  margin-bottom: var(--space-md);
}

.mirror-detail-card {
  padding: var(--space-md);
  background: var(--color-surface);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  font-size: 0.8125rem;
}

.mirror-detail-head {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-xs);
}

.mirror-detail-badge {
  padding: 0.15rem 0.5rem;
  font-size: 0.6875rem;
  font-weight: 600;
  background: #dbeafe;
  color: #1e40af;
  border-radius: 4px;
}

.mirror-detail-region {
  font-weight: 600;
  color: var(--color-text);
}

.mirror-detail-hint {
  margin: 0 0 var(--space-sm);
  color: var(--color-muted);
}

.mirror-file-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.mirror-file-list li {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin-bottom: 0.25rem;
  color: var(--color-muted);
}

/* 线路对比区 */
.section-mirrors {
  background: var(--color-surface);
  border-block: 1px solid var(--color-border);
}

.mirror-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
}

.mirror-compare-card {
  position: relative;
  padding: var(--space-xl);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg);
  transition: box-shadow var(--transition), border-color var(--transition);
}

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

.mirror-compare-card--cn {
  border-top: 3px solid var(--color-cta);
}

.mirror-compare-card--intl {
  border-top: 3px solid var(--color-accent);
}

.mirror-compare-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  border-radius: 12px;
  margin-bottom: var(--space-md);
  color: var(--color-cta);
}

.mirror-compare-card--intl .mirror-compare-icon {
  color: var(--color-accent);
}

.mirror-compare-badge {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  padding: 0.2rem 0.55rem;
  font-size: 0.6875rem;
  font-weight: 600;
  background: var(--color-cta);
  color: #fff;
  border-radius: 4px;
}

.mirror-compare-badge--intl {
  background: var(--color-accent);
}

.mirror-compare-card h3 {
  margin: 0 0 var(--space-xs);
  font-family: var(--font-heading);
  font-size: 1.125rem;
}

.mirror-compare-region {
  margin: 0 0 var(--space-sm);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-cta);
}

.mirror-compare-card--intl .mirror-compare-region {
  color: var(--color-accent);
}

.mirror-compare-card > p {
  margin: 0 0 var(--space-md);
  font-size: 0.9375rem;
  color: var(--color-muted);
}

.mirror-compare-card ul {
  margin: 0;
  padding-left: 1.1rem;
  font-size: 0.875rem;
  color: var(--color-muted);
}

.mirror-compare-card li {
  margin-bottom: 0.35rem;
}

.download-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

.download-cards--dark .download-card {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.15);
}

.download-cards--dark .download-card h3,
.download-cards--dark .download-card p {
  color: #fff;
}

.download-cards--dark .download-card p {
  opacity: 0.75;
}

.download-cards--dark .download-card:hover {
  border-color: rgba(255, 255, 255, 0.35);
}

.download-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.download-card:hover {
  border-color: #c4b5fd;
  box-shadow: var(--shadow-md);
}

.download-card h3 {
  margin: 0 0 var(--space-xs);
  font-size: 1.0625rem;
  font-family: var(--font-heading);
}

.download-card p {
  margin: 0 0 var(--space-md);
  font-size: 0.875rem;
  color: var(--color-muted);
}

.download-card--recommended {
  border-color: #93c5fd;
  box-shadow: 0 0 0 1px rgba(37, 99, 235, 0.08);
}

.download-card-badge {
  display: inline-block;
  margin-bottom: var(--space-sm);
  padding: 0.15rem 0.5rem;
  font-size: 0.6875rem;
  font-weight: 600;
  color: #fff;
  background: var(--color-success);
  border-radius: 4px;
}

.portable-notice {
  display: flex;
  gap: var(--space-sm);
  align-items: flex-start;
  margin: 0 0 var(--space-md);
  padding: var(--space-sm) var(--space-md);
  font-size: 0.8125rem;
  line-height: 1.5;
  color: #92400e;
  background: #fffbeb;
  border: 1px solid #fcd34d;
  border-radius: 8px;
}

.portable-notice-icon {
  flex-shrink: 0;
  margin-top: 0.1rem;
  color: #d97706;
}

.portable-notice p {
  margin: 0;
  font-size: inherit;
  color: inherit;
}

.portable-notice strong {
  color: #78350f;
}

.portable-notice--dark {
  color: #fde68a;
  background: rgba(251, 191, 36, 0.12);
  border-color: rgba(251, 191, 36, 0.35);
}

.portable-notice--dark strong {
  color: #fef3c7;
}

.portable-notice--dark .portable-notice-icon {
  color: #fbbf24;
}

.download-cards--dark .download-card--recommended {
  border-color: rgba(16, 185, 129, 0.5);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.75rem 1.25rem;
  border: none;
  border-radius: 8px;
  font-family: var(--font-body);
  font-size: 0.9375rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), opacity var(--transition);
}

.btn:focus-visible {
  outline: 2px solid var(--color-cta);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--color-cta);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-cta-hover);
}

.btn-secondary {
  background: var(--color-primary);
  color: #fff;
}

.btn-secondary:hover {
  background: #27272a;
}

.btn:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

.btn-icon {
  width: 1.125rem;
  height: 1.125rem;
  flex-shrink: 0;
}

/* SVG 的 hidden 在部分浏览器无效，用 class 控制加载圈 */
.btn-spinner {
  display: none !important;
  width: 1.125rem;
  height: 1.125rem;
}

.btn.is-loading .btn-spinner {
  display: inline-block !important;
  animation: btn-spin 0.7s linear infinite;
}

.btn.is-loading .btn-download-icon {
  display: none;
}

@keyframes btn-spin {
  to {
    transform: rotate(360deg);
  }
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-logo-wrap {
  position: relative;
  width: min(380px, 100%);
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 24px;
  box-shadow: var(--shadow-lg);
}

.hero-logo-wrap::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: 24px;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.12), transparent 50%);
  pointer-events: none;
}

.hero-logo-wrap img {
  width: 55%;
  position: relative;
  z-index: 1;
}

.stats-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-lg) var(--space-xl);
  margin-top: var(--space-2xl);
  padding: var(--space-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.stat-item {
  min-width: 4.5rem;
}

.stat-item strong {
  display: block;
  font-size: 1.5rem;
  font-family: var(--font-heading);
  color: var(--color-primary);
}

.stat-item span {
  font-size: 0.8125rem;
  color: var(--color-muted);
}

/* Sections */
.section {
  padding: var(--space-3xl) 0;
}

.section-header {
  text-align: center;
  max-width: 36rem;
  margin: 0 auto var(--space-2xl);
}

.section-header h2 {
  font-family: var(--font-heading);
  font-size: clamp(1.5rem, 3vw, 2rem);
  margin: 0 0 var(--space-sm);
}

.section-header p {
  margin: 0;
  color: var(--color-muted);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: box-shadow var(--transition);
}

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

.feature-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #f4f4f5;
  border-radius: 10px;
  margin-bottom: var(--space-md);
  color: var(--color-primary);
}

.feature-card h3 {
  margin: 0 0 var(--space-sm);
  font-size: 1.0625rem;
  font-family: var(--font-heading);
}

.feature-card p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-muted);
}

/* Requirements */
.req-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

.req-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
}

.req-card h3 {
  margin: 0 0 var(--space-md);
  font-size: 1rem;
  font-family: var(--font-heading);
}

.req-card ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--color-muted);
  font-size: 0.9375rem;
}

.req-card li {
  margin-bottom: var(--space-sm);
}

/* FAQ */
.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--color-border);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-lg) 0;
  background: none;
  border: none;
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  color: var(--color-text);
  cursor: pointer;
  transition: color var(--transition);
}

.faq-question:hover {
  color: var(--color-cta);
}

.faq-question:focus-visible {
  outline: 2px solid var(--color-cta);
  outline-offset: 2px;
}

.faq-icon {
  flex-shrink: 0;
  transition: transform var(--transition);
}

.faq-item.is-open .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 300ms ease;
}

.faq-item.is-open .faq-answer {
  max-height: 200px;
}

.faq-answer-inner {
  padding-bottom: var(--space-lg);
  color: var(--color-muted);
  font-size: 0.9375rem;
}

/* CTA band */
.cta-band {
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  text-align: center;
  margin: var(--space-2xl) 0 0;
}

.cta-band h2 {
  margin: 0 0 var(--space-sm);
  font-family: var(--font-heading);
  font-size: 1.5rem;
}

.cta-band p {
  margin: 0 0 var(--space-lg);
  opacity: 0.85;
}

.cta-band .download-block {
  max-width: 640px;
  margin: 0 auto;
}

.cta-band .download-cards {
  max-width: 100%;
}

/* Footer */
.site-footer {
  padding: var(--space-2xl) 0 var(--space-xl);
  border-top: 1px solid var(--color-border);
  text-align: center;
  color: var(--color-muted);
  font-size: 0.875rem;
}

.site-footer .footer-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
  color: var(--color-text);
  font-weight: 600;
}

.site-footer img {
  width: 28px;
  height: 28px;
}

/* Toast */
.toast {
  position: fixed;
  bottom: var(--space-lg);
  left: 50%;
  transform: translateX(-50%) translateY(120%);
  padding: 0.75rem 1.25rem;
  background: var(--color-primary);
  color: #fff;
  border-radius: 8px;
  font-size: 0.875rem;
  box-shadow: var(--shadow-lg);
  z-index: 200;
  transition: transform 300ms ease;
  pointer-events: none;
}

.toast.is-visible {
  transform: translateX(-50%) translateY(0);
}

/* Mobile nav */
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: calc(100% + var(--space-sm));
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: var(--space-md);
    box-shadow: var(--shadow-md);
  }

  .nav-links.is-open {
    display: flex;
  }

  .hero-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }

  .hero-visual {
    order: -1;
  }

  .hero-logo-wrap {
    width: min(280px, 80vw);
    margin: 0 auto;
  }

  .download-cards,
  .features-grid,
  .req-grid,
  .mirror-compare,
  .mirror-switch {
    grid-template-columns: 1fr;
  }

  .mirror-tab-badge {
    position: static;
    align-self: flex-start;
    margin-top: 0.25rem;
  }

  .site-nav {
    top: var(--space-sm);
    left: var(--space-sm);
    right: var(--space-sm);
    padding: 0 var(--space-md);
  }
}

@media (max-width: 375px) {
  .hero h1 {
    font-size: 1.75rem;
  }
}