/* IELTS Mate — Official Homepage */

:root {
  --primary: #1a365d;
  --primary-light: #2b6cb0;
  --accent: #ed8936;
  --accent-light: #f6ad55;
  --success: #48bb78;
  --bg: #f7fafc;
  --card: #ffffff;
  --text: #1a202c;
  --muted: #4a5568;
  --border: #e2e8f0;
  --hero-glow: rgba(237, 137, 54, 0.18);
  --shadow: 0 12px 40px rgba(26, 54, 93, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body.home {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: min(1120px, calc(100% - 3rem));
  margin: 0 auto;
}

/* Nav */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(247, 250, 252, 0.88);
  border-bottom: 1px solid var(--border);
}

.site-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-weight: 700;
  color: var(--primary);
}

.brand-mark {
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 0.65rem;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 0.95rem;
  font-weight: 800;
  box-shadow: 0 4px 14px rgba(26, 54, 93, 0.25);
}

.brand small {
  display: block;
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.92rem;
  color: var(--muted);
}

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

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.55rem 1rem;
  border-radius: 999px;
  background: var(--accent);
  color: #fff !important;
  font-weight: 600;
  box-shadow: 0 6px 18px rgba(237, 137, 54, 0.35);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 22px rgba(237, 137, 54, 0.42);
}

/* Hero */
.hero {
  position: relative;
  overflow: hidden;
  padding: 4.5rem 0 5rem;
  background:
    radial-gradient(circle at 85% 15%, var(--hero-glow), transparent 42%),
    linear-gradient(160deg, #edf2f7 0%, #f7fafc 55%, #fff 100%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 3rem;
  align-items: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  background: #ebf8ff;
  color: var(--primary);
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.hero h1 {
  margin: 0 0 1rem;
  font-size: clamp(2.1rem, 4vw, 3.2rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--primary);
}

.hero h1 span {
  color: var(--accent);
}

.hero-lead {
  margin: 0 0 1.75rem;
  font-size: 1.08rem;
  color: var(--muted);
  max-width: 34rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-bottom: 2rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.85rem 1.35rem;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  color: #fff;
  box-shadow: 0 10px 24px rgba(237, 137, 54, 0.35);
}

.btn-secondary {
  background: #fff;
  color: var(--primary);
  border: 1px solid var(--border);
}

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.stat strong {
  display: block;
  font-size: 1.35rem;
  color: var(--primary);
}

.stat span {
  font-size: 0.85rem;
  color: var(--muted);
}

/* Phone mockup */
.phone-wrap {
  position: relative;
  display: flex;
  justify-content: center;
}

.phone-glow {
  position: absolute;
  inset: 10% 5% 0;
  background: radial-gradient(circle, rgba(43, 108, 176, 0.22), transparent 70%);
  filter: blur(18px);
}

.phone {
  position: relative;
  width: min(320px, 100%);
  border-radius: 2rem;
  padding: 0.75rem;
  background: linear-gradient(160deg, #2d3748, #1a202c);
  box-shadow: var(--shadow);
}

.phone-screen {
  border-radius: 1.5rem;
  overflow: hidden;
  background: #fff;
}

.phone-top {
  padding: 1rem 1rem 0.75rem;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: #fff;
}

.phone-top h3 {
  margin: 0;
  font-size: 1rem;
}

.phone-top p {
  margin: 0.25rem 0 0;
  font-size: 0.78rem;
  opacity: 0.9;
}

.phone-body {
  padding: 1rem;
}

.mini-card {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.85rem;
  margin-bottom: 0.65rem;
  background: #fff;
}

.mini-card h4 {
  margin: 0 0 0.35rem;
  font-size: 0.82rem;
  color: var(--primary);
}

.mini-card p {
  margin: 0;
  font-size: 0.75rem;
  color: var(--muted);
}

.progress-bar {
  height: 6px;
  border-radius: 999px;
  background: #edf2f7;
  overflow: hidden;
  margin-top: 0.55rem;
}

.progress-bar span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), var(--success));
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.65rem;
}

.chip {
  font-size: 0.68rem;
  padding: 0.2rem 0.5rem;
  border-radius: 999px;
  background: #ebf8ff;
  color: var(--primary);
}

/* Sections */
section {
  padding: 4.5rem 0;
}

.section-head {
  text-align: center;
  max-width: 40rem;
  margin: 0 auto 2.75rem;
}

.section-head h2 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  color: var(--primary);
}

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

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.feature-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.35rem;
  box-shadow: 0 4px 18px rgba(26, 54, 93, 0.05);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.feature-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 28px rgba(26, 54, 93, 0.1);
}

.feature-icon {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 10px;
  display: grid;
  place-items: center;
  background: #ebf8ff;
  color: var(--primary);
  font-size: 1.1rem;
  margin-bottom: 0.85rem;
}

.feature-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.02rem;
  color: var(--primary);
}

.feature-card p {
  margin: 0;
  font-size: 0.92rem;
  color: var(--muted);
}

/* Steps */
.steps {
  background: #fff;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.step {
  text-align: center;
  padding: 1.25rem;
}

.step-num {
  width: 2.5rem;
  height: 2.5rem;
  margin: 0 auto 1rem;
  border-radius: 999px;
  display: grid;
  place-items: center;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
}

.step h3 {
  margin: 0 0 0.5rem;
  color: var(--primary);
}

.step p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

/* Platforms */
.platforms {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}

.platform-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.1rem;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--border);
  color: var(--primary);
  font-weight: 600;
  font-size: 0.9rem;
}

/* CTA band */
.cta-band {
  padding: 3.5rem 0;
}

.cta-card {
  border-radius: 20px;
  padding: 2.5rem;
  text-align: center;
  color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  box-shadow: var(--shadow);
}

.cta-card h2 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.5rem, 3vw, 2rem);
}

.cta-card p {
  margin: 0 auto 1.5rem;
  max-width: 32rem;
  opacity: 0.92;
}

.cta-card .btn-primary {
  background: #fff;
  color: var(--primary);
  box-shadow: none;
}

/* Footer */
.site-footer {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.88rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-grid h4 {
  margin: 0 0 0.75rem;
  color: var(--primary);
  font-size: 0.95rem;
}

.footer-grid ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-grid li {
  margin-bottom: 0.45rem;
}

.footer-grid a:hover {
  color: var(--primary);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.75rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
}

/* Mobile nav */
.menu-toggle {
  display: none;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 8px;
  padding: 0.4rem 0.65rem;
  color: var(--primary);
}

@media (max-width: 900px) {
  .hero-grid,
  .features-grid,
  .steps-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 3rem;
  }

  .phone-wrap {
    order: -1;
  }

  .nav-links {
    display: none;
  }

  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(247, 250, 252, 0.98);
    border-bottom: 1px solid var(--border);
    padding: 1rem 1.5rem 1.25rem;
  }

  .menu-toggle {
    display: inline-block;
  }

  .site-nav .container {
    position: relative;
    flex-wrap: wrap;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --card: #1e293b;
    --text: #f1f5f9;
    --muted: #cbd5e1;
    --border: #334155;
    --hero-glow: rgba(237, 137, 54, 0.12);
    --shadow: 0 12px 40px rgba(0, 0, 0, 0.35);
  }

  .site-nav {
    background: rgba(15, 23, 42, 0.9);
  }

  .hero {
    background:
      radial-gradient(circle at 85% 15%, var(--hero-glow), transparent 42%),
      linear-gradient(160deg, #0f172a 0%, #1e293b 55%, #0f172a 100%);
  }

  .eyebrow,
  .feature-icon,
  .chip {
    background: #1e3a5f;
  }

  .btn-secondary,
  .platform-pill {
    background: #1e293b;
  }

  .steps {
    background: #0f172a;
  }

  .mini-card {
    background: #1e293b;
  }
}