* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", Arial, sans-serif;
  color: #eef2ff;
  background:
    radial-gradient(circle at top left, rgba(59, 130, 246, 0.18), transparent 28%),
    radial-gradient(circle at bottom right, rgba(139, 92, 246, 0.18), transparent 30%),
    linear-gradient(135deg, #060816 0%, #0b1224 50%, #0d1328 100%);
  min-height: 100vh;
  overflow-x: hidden;
}

a {
  text-decoration: none;
}

.container {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
}

.background-glow {
  position: fixed;
  width: 420px;
  height: 420px;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.18;
  pointer-events: none;
  z-index: 0;
}

.glow-1 {
  top: -100px;
  left: -120px;
  background: #3b82f6;
}

.glow-2 {
  right: -120px;
  bottom: -80px;
  background: #8b5cf6;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(16px);
  background: rgba(8, 12, 28, 0.58);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.nav {
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 18px;
  color: #ffffff;
}

.brand-logo {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-weight: 800;
  background: linear-gradient(135deg, #60a5fa, #8b5cf6);
  color: white;
  box-shadow: 0 10px 24px rgba(99, 102, 241, 0.35);
}

.nav-links {
  display: flex;
  gap: 28px;
}

.nav-links a {
  color: #cbd5e1;
  font-size: 15px;
  transition: 0.25s ease;
}

.nav-links a:hover {
  color: white;
}

.nav-button,
.primary-button,
.secondary-button {
  transition: all 0.25s ease;
}

.nav-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  color: white;
  font-weight: 600;
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.nav-button:hover {
  background: rgba(255, 255, 255, 0.14);
}

.hero {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 42px;
  align-items: center;
  padding: 72px 0 40px;
}

.badge,
.mini-badge {
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  color: #dbeafe;
  background: rgba(96, 165, 250, 0.12);
  border: 1px solid rgba(96, 165, 250, 0.18);
}

.hero h1 {
  margin: 20px 0 18px;
  font-size: clamp(48px, 7vw, 76px);
  line-height: 0.98;
  letter-spacing: -2px;
  color: #ffffff;
}

.hero h1 span {
  background: linear-gradient(90deg, #93c5fd, #c4b5fd);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-text {
  max-width: 640px;
  color: #cbd5e1;
  font-size: 18px;
  line-height: 1.85;
  margin-bottom: 28px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: 22px;
}

.primary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 16px 24px;
  border-radius: 16px;
  background: linear-gradient(135deg, #f8fafc, #dbeafe);
  color: #0f172a;
  font-weight: 700;
  box-shadow: 0 18px 36px rgba(255, 255, 255, 0.12);
}

.primary-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 22px 40px rgba(255, 255, 255, 0.18);
}

.primary-button.large {
  padding: 18px 28px;
}

.secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 16px 24px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.06);
  color: white;
  font-weight: 600;
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.secondary-button:hover {
  background: rgba(255, 255, 255, 0.11);
  transform: translateY(-2px);
}

.hero-note {
  color: #94a3b8;
  font-size: 14px;
  line-height: 1.8;
}

.app-preview {
  background: rgba(11, 18, 36, 0.82);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 28px;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.35);
  overflow: hidden;
}

.app-topbar {
  display: flex;
  gap: 8px;
  padding: 16px 18px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  background: rgba(255, 255, 255, 0.02);
}

.app-topbar span {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
}

.app-body {
  display: grid;
  grid-template-columns: 190px 1fr;
  min-height: 420px;
}

.preview-sidebar {
  padding: 18px;
  border-right: 1px solid rgba(255, 255, 255, 0.06);
  background: rgba(255, 255, 255, 0.02);
}

.sidebar-item {
  padding: 12px 14px;
  border-radius: 14px;
  color: #cbd5e1;
  margin-bottom: 10px;
  font-size: 14px;
}

.sidebar-item.active {
  background: rgba(96, 165, 250, 0.14);
  color: white;
}

.preview-content {
  padding: 22px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.chat-card,
.analysis-panel {
  border-radius: 20px;
  padding: 18px;
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.chat-card {
  background: rgba(255, 255, 255, 0.04);
}

.chat-card.student {
  background: rgba(139, 92, 246, 0.08);
}

.chat-label {
  font-size: 12px;
  font-weight: 700;
  color: #93c5fd;
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.chat-card p,
.analysis-panel li {
  color: #dbe4f0;
  line-height: 1.75;
  margin: 0;
}

.analysis-panel {
  background: rgba(96, 165, 250, 0.07);
}

.analysis-panel h3 {
  margin: 0 0 10px;
  font-size: 16px;
}

.analysis-panel ul {
  padding-left: 18px;
  margin: 0;
}

.stats {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-top: 18px;
}

.stat-card,
.feature-card,
.step-card,
.download-card,
.notice-card {
  background: rgba(11, 18, 36, 0.72);
  border: 1px solid rgba(255, 255, 255, 0.07);
  box-shadow: 0 18px 48px rgba(0, 0, 0, 0.22);
}

.stat-card {
  padding: 24px;
  border-radius: 22px;
}

.stat-card h3 {
  margin: 0 0 10px;
  font-size: 18px;
  color: white;
}

.stat-card p {
  margin: 0;
  color: #cbd5e1;
  line-height: 1.7;
}

.section {
  position: relative;
  z-index: 1;
  padding: 82px 0 0;
}

.section-heading {
  max-width: 720px;
  margin-bottom: 28px;
}

.section-heading h2 {
  margin: 14px 0 12px;
  font-size: clamp(34px, 5vw, 48px);
  color: white;
  letter-spacing: -1px;
}

.section-heading p {
  margin: 0;
  color: #cbd5e1;
  line-height: 1.8;
  font-size: 17px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.feature-card {
  padding: 28px;
  border-radius: 24px;
}

.feature-card h3 {
  margin: 0 0 12px;
  color: white;
  font-size: 20px;
}

.feature-card p {
  margin: 0;
  color: #cbd5e1;
  line-height: 1.8;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.step-card {
  padding: 28px;
  border-radius: 24px;
}

.step-number {
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  margin-bottom: 18px;
  font-weight: 800;
  background: linear-gradient(135deg, #60a5fa, #8b5cf6);
  color: white;
}

.step-card h3 {
  margin: 0 0 10px;
  color: white;
}

.step-card p {
  margin: 0;
  color: #cbd5e1;
  line-height: 1.8;
}

.download-section {
  padding: 82px 0 0;
  position: relative;
  z-index: 1;
}

.download-card {
  border-radius: 30px;
  padding: 34px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 28px;
}

.download-card h2 {
  margin: 14px 0 12px;
  font-size: clamp(30px, 4vw, 42px);
  color: white;
}

.download-card p {
  margin: 0;
  color: #cbd5e1;
  line-height: 1.8;
  max-width: 720px;
}

.notice-card {
  padding: 28px;
  border-radius: 24px;
}

.notice-card h3 {
  margin: 0 0 12px;
  color: white;
}

.notice-card p {
  margin: 0;
  color: #cbd5e1;
  line-height: 1.85;
}

.site-footer {
  position: relative;
  z-index: 1;
  padding: 70px 0 36px;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  gap: 30px;
  align-items: flex-start;
  border-top: 1px solid rgba(255, 255, 255, 0.07);
  padding-top: 28px;
}

.footer-brand {
  margin-bottom: 14px;
}

.footer-text {
  max-width: 420px;
  color: #94a3b8;
  line-height: 1.8;
  margin: 0;
}

.footer-links {
  display: flex;
  gap: 22px;
  flex-wrap: wrap;
}

.footer-links a {
  color: #cbd5e1;
}

.footer-links a:hover {
  color: white;
}

@media (max-width: 980px) {
  .hero {
    grid-template-columns: 1fr;
  }

  .stats,
  .steps,
  .feature-grid {
    grid-template-columns: 1fr;
  }

  .download-card {
    flex-direction: column;
    align-items: flex-start;
  }

  .app-body {
    grid-template-columns: 1fr;
  }

  .preview-sidebar {
    border-right: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  }
}

@media (max-width: 760px) {
  .nav-links {
    display: none;
  }

  .nav {
    height: 74px;
  }

  .hero {
    padding-top: 44px;
  }

  .hero h1 {
    letter-spacing: -1px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .primary-button,
  .secondary-button,
  .nav-button {
    width: 100%;
    text-align: center;
  }

  .footer-content {
    flex-direction: column;
  }
}