/* ═══════════════════════════════════════
   index.css — 校易通 Launch Page
   Aesthetic: Campus Energy × Glassmorphism
   ═══════════════════════════════════════ */

/* ── Preloader ── */
.preloader {
  position: fixed; inset: 0; z-index: 999;
  display: grid; place-items: center;
  background: linear-gradient(135deg, #f8fafc 0%, #eef2ff 50%, #ecfeff 100%);
}
.preloader-inner { text-align: center; }
.preloader-logo { margin-bottom: 24px; animation: preloaderPulse 1.2s ease-in-out infinite; }
@keyframes preloaderPulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.08); }
}
.preloader-bar {
  width: 180px; height: 4px; border-radius: 999px;
  background: rgba(79, 70, 229, 0.15); overflow: hidden; margin: 0 auto 16px;
}
.preloader-bar-fill {
  width: 0%; height: 100%; border-radius: 999px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  animation: preloaderFill 1.4s ease-out forwards;
}
@keyframes preloaderFill { to { width: 100%; } }
.preloader-text {
  color: var(--muted); font-size: 13px; font-weight: 700;
  letter-spacing: 2px; text-transform: uppercase;
}
.preloader.done {
  opacity: 0; pointer-events: none;
  transition: opacity 0.4s ease;
}

/* ── App fade-in ── */
#app { opacity: 0; }
#app.visible { opacity: 1; transition: opacity 0.5s ease 0.1s; }

/* ── Hero Section ── */
.hero {
  position: relative;
  display: grid;
  grid-template-columns: 1.3fr 0.7fr;
  gap: 40px;
  align-items: center;
  min-height: calc(100vh - 140px);
  padding: 60px 0 40px;
  overflow: hidden;
}

/* Hero Background Orbs */
.hero-bg {
  position: absolute; inset: 0;
  pointer-events: none; z-index: 0;
}
.orb {
  position: absolute; border-radius: 50%;
  filter: blur(80px); opacity: 0.5;
}
.orb-1 {
  width: 500px; height: 500px;
  top: -120px; left: -100px;
  background: radial-gradient(circle, rgba(79,70,229,0.35), transparent 70%);
}
.orb-2 {
  width: 400px; height: 400px;
  top: 50%; right: -80px;
  background: radial-gradient(circle, rgba(6,182,212,0.3), transparent 70%);
}
.orb-3 {
  width: 300px; height: 300px;
  bottom: -60px; left: 40%;
  background: radial-gradient(circle, rgba(245,158,11,0.2), transparent 70%);
}
.hero-grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(79,70,229,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(79,70,229,0.04) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, black, transparent);
}

/* Hero Content */
.hero-content {
  position: relative; z-index: 2;
}
.hero-badge {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 10px 18px; border-radius: 999px;
  background: rgba(79, 70, 229, 0.08);
  border: 1px solid rgba(79, 70, 229, 0.15);
  font-size: 14px; font-weight: 800; color: var(--primary-dark);
  margin-bottom: 28px;
  opacity: 0; transform: translateY(20px);
}
.badge-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--success);
  animation: dotPulse 2s ease-in-out infinite;
}
@keyframes dotPulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(34,197,94,0.4); }
  50% { box-shadow: 0 0 0 6px rgba(34,197,94,0); }
}

.hero-headline {
  font-size: clamp(42px, 5.5vw, 78px);
  line-height: 1.02; letter-spacing: -3.5px;
  margin-bottom: 24px; font-weight: 950;
}
.hero-line {
  display: block;
  opacity: 0; transform: translateY(40px);
}
.hero-desc {
  max-width: 560px; color: #475569;
  font-size: 17px; line-height: 1.85;
  margin-bottom: 36px;
  opacity: 0; transform: translateY(20px);
}
.hero-actions {
  display: flex; gap: 14px; flex-wrap: wrap;
  margin-bottom: 48px;
  opacity: 0; transform: translateY(20px);
}
.hero-cta {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 15px; padding: 0 24px; min-height: 50px;
}
.hero-cta svg { transition: transform 0.3s ease; }
.hero-cta:hover svg { transform: translateX(4px); }

/* Hero Stats Bar */
.hero-stats {
  display: flex; align-items: center; gap: 0;
  padding: 20px 28px; border-radius: 22px;
  background: rgba(255,255,255,0.7);
  backdrop-filter: blur(20px);
  border: 1px solid var(--line);
  box-shadow: 0 12px 40px rgba(15,23,42,0.08);
  opacity: 0; transform: translateY(30px);
}
.hero-stat { flex: 1; text-align: center; }
.hero-stat strong {
  display: block; font-size: 28px; font-weight: 950;
  color: var(--text); letter-spacing: -1px;
}
.hero-stat span {
  display: block; margin-top: 4px;
  font-size: 12px; font-weight: 700; color: var(--muted);
  text-transform: uppercase; letter-spacing: 1px;
}
.hero-stat-divider {
  width: 1px; height: 36px;
  background: var(--line);
}

/* Hero Visual (Floating Cards) */
.hero-visual {
  position: relative; z-index: 2;
  display: flex; justify-content: center; align-items: center;
  min-height: 420px;
}
.hero-card-stack {
  position: relative;
  width: 300px; height: 380px;
}
.floating-card {
  position: absolute;
  display: flex; align-items: center; gap: 14px;
  padding: 16px 20px; border-radius: 20px;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(16px);
  border: 1px solid var(--line);
  box-shadow: 0 16px 48px rgba(15,23,42,0.1);
  opacity: 0; transform: translateY(30px) scale(0.9);
  cursor: default;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.floating-card:hover {
  transform: translateY(-4px) scale(1.03) !important;
  box-shadow: 0 24px 60px rgba(15,23,42,0.15);
}
.fc-icon {
  width: 48px; height: 48px;
  display: grid; place-items: center;
  border-radius: 14px; font-size: 24px;
  background: linear-gradient(135deg, rgba(79,70,229,0.1), rgba(6,182,212,0.1));
}
.fc-text strong { display: block; font-size: 15px; font-weight: 900; }
.fc-text span { font-size: 13px; color: var(--muted); font-weight: 700; }

.fc-1 { top: 0; left: 10px; }
.fc-2 { top: 90px; right: 0; }
.fc-3 { top: 190px; left: 20px; }
.fc-4 { top: 280px; right: 10px; }

/* ── Section Headers ── */
.section-header {
  text-align: center;
  margin-bottom: 48px;
}
.section-tag {
  display: inline-block;
  padding: 8px 16px; border-radius: 999px;
  background: rgba(79,70,229,0.08);
  color: var(--primary-dark);
  font-size: 13px; font-weight: 800;
  letter-spacing: 1px; text-transform: uppercase;
  margin-bottom: 18px;
}
.section-heading {
  font-size: clamp(30px, 4vw, 52px);
  line-height: 1.1; letter-spacing: -2px;
  font-weight: 950; margin-bottom: 16px;
}
.section-sub {
  max-width: 520px; margin: 0 auto;
  color: var(--muted); font-size: 16px; line-height: 1.7;
}

/* ── Features Section ── */
.features {
  padding: 80px 0 40px;
}
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.feature-card {
  padding: 32px 24px; border-radius: 28px;
  background: rgba(255,255,255,0.7);
  backdrop-filter: blur(20px);
  border: 1px solid var(--line);
  box-shadow: 0 8px 32px rgba(15,23,42,0.06);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  opacity: 0; transform: translateY(40px);
}
.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 60px rgba(15,23,42,0.12);
}
.feature-icon {
  width: 56px; height: 56px;
  display: grid; place-items: center;
  border-radius: 18px;
  background: linear-gradient(135deg, rgba(79,70,229,0.12), rgba(6,182,212,0.08));
  color: var(--primary);
  margin-bottom: 20px;
}
.feature-card h3 {
  font-size: 19px; font-weight: 900;
  margin-bottom: 10px; letter-spacing: -0.5px;
}
.feature-card p {
  color: var(--muted); font-size: 14px;
  line-height: 1.7;
}

/* ── How It Works ── */
.how-it-works {
  padding: 80px 0 40px;
}
.steps-track {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  position: relative;
}
.steps-line {
  position: absolute;
  top: 48px; left: 16.67%; right: 16.67%;
  height: 3px; border-radius: 999px;
  background: var(--line);
  z-index: 0;
}
.steps-line::after {
  content: "";
  position: absolute; left: 0; top: 0;
  height: 100%; width: 0%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  transition: width 1s ease;
}
.steps-line.animate::after { width: 100%; }

.step-card {
  position: relative; z-index: 1;
  text-align: center;
  padding: 0 20px;
  opacity: 0; transform: translateY(40px);
}
.step-number {
  font-size: 64px; font-weight: 950;
  letter-spacing: -4px;
  background: linear-gradient(180deg, rgba(79,70,229,0.12), transparent);
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
  line-height: 1; margin-bottom: 8px;
}
.step-icon-wrap {
  width: 72px; height: 72px;
  margin: 0 auto 20px;
  display: grid; place-items: center;
  border-radius: 22px;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(16px);
  border: 1px solid var(--line);
  box-shadow: 0 12px 36px rgba(15,23,42,0.08);
  color: var(--primary);
}
.step-card h3 {
  font-size: 18px; font-weight: 900;
  margin-bottom: 10px;
}
.step-card p {
  color: var(--muted); font-size: 14px;
  line-height: 1.7; max-width: 260px; margin: 0 auto;
}

/* ── Platform Stats ── */
.platform-stats {
  padding: 60px 0;
}
.stats-card {
  padding: 48px; border-radius: 32px;
  background: linear-gradient(135deg, rgba(17,24,39,0.97), rgba(55,48,163,0.95));
  box-shadow: 0 32px 80px rgba(15,23,42,0.25);
  color: white;
  opacity: 0; transform: translateY(40px);
}
.stats-header {
  text-align: center; margin-bottom: 40px;
}
.stats-header h2 {
  font-size: clamp(26px, 3.5vw, 42px);
  letter-spacing: -2px; font-weight: 950;
  margin-bottom: 8px;
}
.stats-header p {
  color: rgba(255,255,255,0.55); font-size: 15px;
}
.stats-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}
.stat-block { text-align: center; }
.stat-num {
  font-size: clamp(36px, 4vw, 56px);
  font-weight: 950; letter-spacing: -2px;
  line-height: 1;
}
.stat-label {
  font-size: 14px; font-weight: 700;
  color: rgba(255,255,255,0.6);
  margin-top: 8px; margin-bottom: 16px;
}
.stat-bar {
  height: 4px; border-radius: 999px;
  background: rgba(255,255,255,0.15);
  overflow: hidden; max-width: 120px; margin: 0 auto;
}
.stat-bar-fill {
  height: 100%; border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), #22d3ee);
  transition: width 1.5s cubic-bezier(0.22, 1, 0.36, 1);
}

/* ── Products Section ── */
.products-section {
  padding: 60px 0;
}
.products-cta {
  text-align: center; margin-top: 32px;
}

/* ── CTA Section ── */
.cta-section {
  padding: 40px 0 60px;
}
.cta-card {
  position: relative; overflow: hidden;
  text-align: center;
  padding: 72px 40px; border-radius: 36px;
  background: rgba(255,255,255,0.75);
  backdrop-filter: blur(24px);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  opacity: 0; transform: translateY(40px);
}
.cta-orb {
  position: absolute; border-radius: 50%;
  filter: blur(60px); pointer-events: none;
}
.cta-orb-1 {
  width: 300px; height: 300px;
  top: -100px; left: -80px;
  background: rgba(79,70,229,0.2);
}
.cta-orb-2 {
  width: 250px; height: 250px;
  bottom: -80px; right: -60px;
  background: rgba(6,182,212,0.18);
}
.cta-card h2 {
  position: relative; z-index: 1;
  font-size: clamp(28px, 3.5vw, 46px);
  letter-spacing: -2px; font-weight: 950;
  margin-bottom: 16px;
}
.cta-card p {
  position: relative; z-index: 1;
  color: var(--muted); font-size: 16px;
  line-height: 1.7; max-width: 480px;
  margin: 0 auto 32px;
}
.cta-actions {
  position: relative; z-index: 1;
  display: flex; gap: 14px;
  justify-content: center; flex-wrap: wrap;
}
.cta-btn {
  min-height: 50px; padding: 0 28px; font-size: 15px;
}

/* ── Footer ── */
.site-footer {
  padding: 32px 0;
  border-top: 1px solid var(--line);
}
.footer-inner {
  display: flex; align-items: center;
  justify-content: space-between; gap: 18px;
  flex-wrap: wrap;
}
.footer-brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 900; font-size: 15px;
}
.footer-copy {
  color: var(--muted); font-size: 13px;
}
.footer-links {
  display: flex; gap: 20px;
}
.footer-links a {
  color: var(--muted); font-size: 13px;
  text-decoration: none; font-weight: 700;
  transition: color 0.2s ease;
}
.footer-links a:hover { color: var(--primary); }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: rgba(79,70,229,0.2); border-radius: 999px;
}

/* ═══════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════ */
@media (max-width: 1100px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto; padding-top: 40px;
  }
  .hero-visual { display: none; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .hero-stats {
    flex-wrap: wrap; gap: 16px;
    padding: 20px;
  }
  .hero-stat-divider { display: none; }
  .hero-stat { flex: 1 1 40%; }
  .hero-headline { letter-spacing: -2px; }
  .hero-card { padding: 28px; }
  .features-grid { grid-template-columns: 1fr; }
  .steps-track { grid-template-columns: 1fr; gap: 32px; }
  .steps-line { display: none; }
  .stats-row { grid-template-columns: 1fr; gap: 24px; }
  .stats-card { padding: 32px 24px; }
  .cta-card { padding: 48px 24px; }
  .footer-inner { flex-direction: column; text-align: center; }
}

@media (max-width: 480px) {
  .hero-actions { flex-direction: column; }
  .hero-actions a { width: 100%; text-align: center; }
  .cta-actions { flex-direction: column; }
  .cta-actions a { width: 100%; text-align: center; }
}