/* ============================================
   学生.top — Design Tokens
   ============================================ */

:root {
  /* Color Palette */
  --ink: #0B1426;
  --paper: #F8F6F1;
  --primary: #2563EB;
  --accent: #F59E0B;
  --muted: #64748B;
  --border: #E2E0DB;
  --surface: #FFFFFF;
  --surface-alt: #F1F0EC;

  /* Typography */
  --font-display: 'Georgia', 'Times New Roman', 'Noto Serif SC', serif;
  --font-body: 'Avenir Next', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
  --font-mono: 'SF Mono', 'Cascadia Code', 'Consolas', monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --duration: 0.4s;
}

/* ============================================
   Reset & Base
   ============================================ */

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

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

body {
  font-family: var(--font-body);
  color: var(--ink);
  background-color: var(--paper);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--duration) var(--ease-out);
}

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

/* ============================================
   Navigation
   ============================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: var(--space-md) var(--space-xl);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(248, 246, 241, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid transparent;
  transition: all var(--duration) var(--ease-out);
}

.nav.scrolled {
  border-bottom-color: var(--border);
  background: rgba(248, 246, 241, 0.95);
}

.nav__logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.02em;
}

.nav__logo span {
  color: var(--primary);
}

.nav__links {
  display: flex;
  gap: var(--space-xl);
  list-style: none;
}

.nav__links a {
  color: var(--muted);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  transition: color var(--duration) var(--ease-out);
}

.nav__links a:hover,
.nav__links a.active {
  color: var(--ink);
}

/* ============================================
   Hero Section
   ============================================ */

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: var(--space-4xl) var(--space-xl);
  position: relative;
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  z-index: -1;
  background: 
    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(37, 99, 235, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 80% 80%, rgba(245, 158, 11, 0.06) 0%, transparent 50%);
}

.hero__eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: var(--space-lg);
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 0.2s forwards;
}

.hero__title {
  font-family: var(--font-display);
  font-size: clamp(3rem, 8vw, 6rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-lg);
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 0.4s forwards;
}

.hero__title span {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero__poetry {
  font-family: var(--font-display);
  font-size: clamp(1.125rem, 2.5vw, 1.5rem);
  color: var(--ink);
  max-width: 560px;
  line-height: 1.8;
  margin-bottom: var(--space-2xl);
  min-height: 2em;
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 0.6s forwards;
}

.hero__poetry-text {
  display: inline;
}

.hero__poetry-cursor {
  display: inline-block;
  color: var(--primary);
  animation: blink 1s step-end infinite;
  margin-left: 2px;
  font-weight: 300;
}

.hero__cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  background: var(--ink);
  color: var(--paper);
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: 100px;
  transition: all var(--duration) var(--ease-out);
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 0.8s forwards;
}

.hero__cta:hover {
  background: var(--primary);
  color: var(--paper);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(37, 99, 235, 0.25);
}

.hero__scroll {
  position: absolute;
  bottom: var(--space-2xl);
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  animation: fadeInUp 0.8s var(--ease-out) 1s forwards;
}

.hero__scroll::after {
  content: '';
  display: block;
  width: 1px;
  height: 48px;
  background: linear-gradient(to bottom, var(--muted), transparent);
  margin: var(--space-md) auto 0;
  animation: scrollPulse 2s ease-in-out infinite;
}

/* ============================================
   Page System (SPA Router)
   ============================================ */

.page {
  display: none;
  min-height: 100vh;
  padding-top: 72px;
}

.page.active {
  display: block;
}

.page--hero {
  padding-top: 0;
}

.page__inner {
  padding: var(--space-3xl) var(--space-xl);
}

.page__header {
  margin-bottom: var(--space-2xl);
}

.page__title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

/* ============================================
   Section & Container
   ============================================ */

.container {
  max-width: 1120px;
  margin: 0 auto;
}

.section__eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--primary);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: var(--space-sm);
}

.section__title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

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

.grid-2col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
}

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

/* ============================================
   Panel (About cards)
   ============================================ */

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: var(--space-2xl);
  transition: all var(--duration) var(--ease-out);
}

.panel:hover {
  border-color: var(--primary);
  box-shadow: 0 8px 30px rgba(37, 99, 235, 0.06);
}

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

.about__avatar {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--ink);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 1.5rem;
  color: var(--paper);
  margin-bottom: var(--space-md);
}

.panel__title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-xs);
}

.panel__subtitle {
  color: var(--muted);
  font-size: 0.875rem;
}

.panel__text {
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.7;
  margin-bottom: var(--space-lg);
}

.panel__text code {
  background: var(--surface-alt);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.panel__link {
  display: inline-flex;
  align-items: center;
  font-weight: 500;
  font-size: 0.9375rem;
}

.panel__link::after {
  content: '';
  transition: transform var(--duration) var(--ease-out);
}

.panel__link:hover::after {
  transform: translateX(4px);
}

/* ============================================
   Info Rows
   ============================================ */

.info-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--border);
}

.info-row:last-of-type {
  border-bottom: none;
  margin-bottom: var(--space-lg);
}

.info-label {
  font-size: 0.8125rem;
  color: var(--muted);
  font-family: var(--font-mono);
}

.info-value {
  font-size: 0.875rem;
  font-weight: 500;
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.tech-tag {
  display: inline-block;
  padding: var(--space-xs) var(--space-sm);
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--muted);
}

/* ============================================
   Feature Cards
   ============================================ */

.feature-card {
  padding: var(--space-xl);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  text-align: center;
  transition: all var(--duration) var(--ease-out);
}

.feature-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.06);
}

.feature-card__icon {
  font-size: 1.75rem;
  margin-bottom: var(--space-md);
}

.feature-card__title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.feature-card__desc {
  color: var(--muted);
  font-size: 0.8125rem;
  line-height: 1.5;
}

/* ============================================
   Poetry / Typewriter
   ============================================ */

.poetry-box {
  max-width: 600px;
  margin: 0 auto;
  padding: var(--space-3xl) var(--space-xl);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  text-align: center;
}

.typewriter {
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  color: var(--ink);
  line-height: 1.6;
  min-height: 3em;
  display: flex;
  align-items: center;
  justify-content: center;
}

.typewriter__text {
  display: inline;
}

.typewriter__cursor {
  display: inline-block;
  color: var(--primary);
  animation: blink 1s step-end infinite;
  margin-left: 2px;
  font-weight: 300;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* ============================================
   Contact Rows
   ============================================ */

.contact-row {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--border);
  color: var(--ink);
  transition: color var(--duration) var(--ease-out);
}

.contact-row:last-child {
  border-bottom: none;
}

.contact-row:hover {
  color: var(--primary);
}

.contact-row__icon {
  font-size: 1.125rem;
  width: 24px;
  text-align: center;
}

.contact-row__text {
  font-size: 0.9375rem;
}

/* ============================================
   Link Cards
   ============================================ */

.link-card {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-lg);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  transition: all var(--duration) var(--ease-out);
}

.link-card:hover {
  border-color: var(--primary);
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.08);
  transform: translateY(-2px);
  color: var(--ink);
}

.link-card__icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: var(--surface-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.125rem;
  flex-shrink: 0;
}

.link-card__text {
  flex: 1;
  min-width: 0;
}

.link-card__title {
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 2px;
}

.link-card__url {
  font-size: 0.75rem;
  color: var(--muted);
  font-family: var(--font-mono);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ============================================
   Footer
   ============================================ */

.footer {
  padding: var(--space-2xl) var(--space-xl);
  text-align: center;
  border-top: 1px solid var(--border);
}

.footer__logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.footer__logo span {
  color: var(--primary);
}

.footer__text {
  color: var(--muted);
  font-size: 0.8125rem;
  margin-bottom: var(--space-sm);
}

.footer__links {
  display: flex;
  gap: var(--space-xl);
  justify-content: center;
  list-style: none;
  margin-bottom: var(--space-md);
}

.footer__links a {
  color: var(--muted);
  font-size: 0.8125rem;
  transition: color var(--duration) var(--ease-out);
}

.footer__links a:hover {
  color: var(--ink);
}

/* ============================================
   Animations
   ============================================ */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scrollPulse {
  0%, 100% {
    opacity: 0.4;
    transform: scaleY(1);
  }
  50% {
    opacity: 1;
    transform: scaleY(1.2);
  }
}

.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.8s var(--ease-out),
              transform 0.8s var(--ease-out);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.stagger > * {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s var(--ease-out),
              transform 0.6s var(--ease-out);
}

.stagger.visible > *:nth-child(1) { transition-delay: 0.05s; }
.stagger.visible > *:nth-child(2) { transition-delay: 0.1s; }
.stagger.visible > *:nth-child(3) { transition-delay: 0.15s; }
.stagger.visible > *:nth-child(4) { transition-delay: 0.2s; }
.stagger.visible > *:nth-child(5) { transition-delay: 0.25s; }
.stagger.visible > *:nth-child(6) { transition-delay: 0.3s; }

.stagger.visible > * {
  opacity: 1;
  transform: translateY(0);
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .hero__eyebrow,
  .hero__title,
  .hero__poetry,
  .hero__cta,
  .hero__scroll {
    opacity: 1;
    animation: none;
  }

  .reveal,
  .stagger > * {
    opacity: 1;
    transform: none;
  }
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 960px) {
  .grid-2col {
    grid-template-columns: 1fr;
  }

  .grid-3col {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  .nav {
    padding: var(--space-md);
  }

  .nav__links {
    gap: var(--space-md);
  }

  .nav__links a {
    font-size: 0.8125rem;
  }

  .grid-3col {
    grid-template-columns: 1fr;
  }

  .section {
    padding: var(--space-2xl) var(--space-md);
  }

  .poetry-box {
    padding: var(--space-2xl) var(--space-md);
  }
}