/* ========================================
   main.css — Neumorphism 拟态设计
   黑白主题 · 极简风格
   ======================================== */

/* ----- Reset & Base ----- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg-body: #E4E4E4;
  --bg-card: #E8E8E8;
  --text-primary: #1A1A1A;
  --text-secondary: #555555;
  --text-muted: #888888;
  --shadow-light: #FFFFFF;
  --shadow-dark: #B8B8B8;
  --shadow-darkest: #A0A0A0;
  --border-radius-card: 20px;
  --border-radius-btn: 12px;
  --border-radius-badge: 20px;
  --font-heading: Georgia, 'Times New Roman', serif;
  --font-body: 'Helvetica Neue', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 40px;
  --spacing-xl: 64px;
  --spacing-2xl: 80px;
  --transition: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background: var(--bg-body);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.6;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* ========================================
   Header
   ======================================== */

.header {
  padding: var(--spacing-2xl) 0 var(--spacing-xl);
  text-align: center;
}

.header__title {
  font-family: var(--font-heading);
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
  text-shadow: 2px 2px 4px var(--shadow-dark), -2px -2px 4px var(--shadow-light);
}

.header__subtitle {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-secondary);
  letter-spacing: 0.08em;
  font-weight: 300;
}

/* ========================================
   Grid
   ======================================== */

.main {
  flex: 1;
  padding-bottom: var(--spacing-2xl);
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

/* ========================================
   Card — 拟态凹陷效果
   ======================================== */

.card {
  background: var(--bg-card);
  border-radius: var(--border-radius-card);
  padding: var(--spacing-lg);
  box-shadow:
    inset 6px 6px 12px var(--shadow-dark),
    inset -6px -6px 12px var(--shadow-light);
  transition: box-shadow var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
  position: relative;
}

.card:hover {
  box-shadow:
    inset 4px 4px 8px var(--shadow-dark),
    inset -4px -4px 8px var(--shadow-light);
}

/* ----- Card Header (icon + name + badge) ----- */
.card__header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
  flex-wrap: wrap;
}

.card__icon {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  background: var(--bg-card);
  box-shadow:
    4px 4px 8px var(--shadow-dark),
    -4px -4px 8px var(--shadow-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}

.card__name {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.card__badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  padding: 4px 14px;
  border-radius: var(--border-radius-badge);
  background: var(--bg-card);
  box-shadow:
    inset 2px 2px 5px var(--shadow-dark),
    inset -2px -2px 5px var(--shadow-light);
  color: var(--text-secondary);
  text-transform: uppercase;
  margin-left: auto;
}

/* ----- Card Body ----- */
.card__desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--spacing-md);
  flex: 1;
}

/* ----- Card Action Button — 拟态凸起效果 ----- */
.card__btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border: none;
  border-radius: var(--border-radius-btn);
  background: var(--bg-card);
  box-shadow:
    5px 5px 10px var(--shadow-dark),
    -5px -5px 10px var(--shadow-light);
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition);
  align-self: flex-start;
  text-decoration: none;
  letter-spacing: 0.02em;
}

.card__btn:hover {
  box-shadow:
    3px 3px 6px var(--shadow-dark),
    -3px -3px 6px var(--shadow-light);
  transform: translateY(-1px);
}

.card__btn:active {
  box-shadow:
    inset 3px 3px 6px var(--shadow-dark),
    inset -3px -3px 6px var(--shadow-light);
  transform: translateY(1px);
}

.card__btn .btn__arrow {
  display: inline-block;
  transition: transform var(--transition);
}

.card__btn:hover .btn__arrow {
  transform: translateX(3px);
}

/* ========================================
   Footer — 拟态分隔 + 层次布局
   ======================================== */

.footer {
  padding: 0 0 var(--spacing-lg);
}

.footer__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.footer__divider {
  width: 60px;
  height: 3px;
  border-radius: 2px;
  background: var(--bg-card);
  box-shadow:
    inset 1px 1px 2px var(--shadow-dark),
    inset -1px -1px 2px var(--shadow-light);
  margin-bottom: var(--spacing-md);
}

.footer__content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.footer__brand {
  font-family: var(--font-heading);
  font-size: 0.85rem;
  color: var(--text-primary);
  letter-spacing: 0.04em;
}

.footer__tagline {
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  font-weight: 300;
}

.footer__beian {
  margin-top: 4px;
  font-size: 0.7rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition);
  letter-spacing: 0.02em;
}

.footer__beian:hover {
  color: var(--text-primary);
}

/* ========================================
   Responsive — Tablet
   ======================================== */

@media (max-width: 820px) {
  .grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .header {
    padding: var(--spacing-xl) 0 var(--spacing-lg);
  }

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

/* ========================================
   Responsive — Mobile
   ======================================== */

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-sm);
  }

  .header {
    padding: var(--spacing-lg) 0 var(--spacing-md);
  }

  .grid {
    gap: 24px;
  }

  .card {
    padding: var(--spacing-sm);
    border-radius: 16px;
  }

  .card__name {
    font-size: 1.25rem;
  }

  .card__desc {
    font-size: 0.88rem;
  }

  .card__btn {
    width: 100%;
    justify-content: center;
  }
}

/* ========================================
   Utility — Fade In Animation
   ======================================== */

.card {
  opacity: 0;
  animation: fadeUp 0.6s ease forwards;
}

.card:nth-child(1) { animation-delay: 0.05s; }
.card:nth-child(2) { animation-delay: 0.15s; }
.card:nth-child(3) { animation-delay: 0.25s; }
.card:nth-child(4) { animation-delay: 0.35s; }

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