/* ============================================================
   Math Drill — Website Stylesheet
   Matches exact app color palette (lightTheme / darkTheme)
   ============================================================ */

/* ---------- CSS Variables ---------- */
:root {
  --bg:            #FFFFFF;
  --surface:       #F5F5F5;
  --surface-var:   #E8E8E8;
  --primary:       #2196F3;
  --primary-var:   #1976D2;
  --secondary:     #FF9800;
  --text:          #212121;
  --text-sub:      #757575;
  --correct:       #4CAF50;
  --wrong:         #F44336;
  --border:        #E0E0E0;
  --card:          #FFFFFF;
  --shadow:        rgba(0,0,0,0.10);
  --shadow-lg:     rgba(0,0,0,0.18);
  --radius:        12px;
  --radius-sm:     8px;
  --transition:    0.25s ease;
  --navbar-h:      64px;
}

[data-theme="dark"] {
  --bg:            #121212;
  --surface:       #1E1E1E;
  --surface-var:   #333333;
  --primary:       #64B5F6;
  --primary-var:   #42A5F5;
  --secondary:     #FFA726;
  --text:          #FFFFFF;
  --text-sub:      #B0B0B0;
  --correct:       #66BB6A;
  --wrong:         #EF5350;
  --border:        #484848;
  --card:          #262626;
  --shadow:        rgba(0,0,0,0.35);
  --shadow-lg:     rgba(0,0,0,0.55);
}

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

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background var(--transition), color var(--transition);
  -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; transition: opacity var(--transition); }
a:hover { opacity: 0.8; }
img { max-width: 100%; display: block; }

/* ---------- Utility ---------- */
.container { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
.section { padding: 96px 0; }
.section--tight { padding: 64px 0; }
.text-center { text-align: center; }
.badge {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 4px 12px;
  border-radius: 40px;
  margin-bottom: 16px;
}
.badge--orange { background: var(--secondary); }
.badge--green  { background: var(--correct); }

/* ---------- Navbar ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--navbar-h);
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  transition: background var(--transition), border-color var(--transition);
}
.navbar__inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.navbar__logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 20px;
  color: var(--text);
  text-decoration: none;
}
.navbar__logo-icon {
  width: 36px; height: 36px;
  background: var(--primary);
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px;
  color: #fff;
  font-weight: 900;
  flex-shrink: 0;
}
.navbar__links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}
.navbar__links a {
  color: var(--text-sub);
  font-size: 15px;
  font-weight: 500;
  transition: color var(--transition);
}
.navbar__links a:hover { color: var(--primary); opacity: 1; }
.navbar__right {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Theme toggle */
.theme-toggle {
  width: 44px; height: 44px;
  border-radius: 50%;
  border: 1.5px solid var(--border);
  background: var(--surface);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px;
  transition: background var(--transition), border-color var(--transition);
  flex-shrink: 0;
}
.theme-toggle:hover { background: var(--surface-var); }

/* Menu toggle (mobile) */
.menu-toggle {
  display: none;
  width: 44px; height: 44px;
  border: none;
  background: transparent;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border-radius: 8px;
}
.menu-toggle span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.3s, opacity 0.3s;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  border: none;
  transition: transform 0.15s, box-shadow 0.15s, opacity var(--transition);
  text-decoration: none;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 8px 24px var(--shadow-lg); opacity: 1; }
.btn:active { transform: translateY(0); }

.btn--primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 14px color-mix(in srgb, var(--primary) 30%, transparent);
}
.btn--secondary {
  background: var(--surface-var);
  color: var(--text);
  border: 1.5px solid var(--border);
}
.btn--outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}
.btn--lg { padding: 16px 36px; font-size: 16px; border-radius: var(--radius); }

/* ---------- Hero ---------- */
.hero {
  padding: 100px 0 80px;
  overflow: hidden;
  position: relative;
}
.hero::before {
  content: '';
  position: absolute;
  top: -200px; right: -200px;
  width: 600px; height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, color-mix(in srgb, var(--primary) 12%, transparent), transparent 70%);
  pointer-events: none;
}
.hero__inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.hero__eyebrow {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 16px;
}
.hero__title {
  font-size: clamp(36px, 5vw, 58px);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  color: var(--text);
}
.hero__title span { color: var(--primary); }
.hero__subtitle {
  font-size: 18px;
  color: var(--text-sub);
  margin-bottom: 36px;
  max-width: 480px;
  line-height: 1.7;
}
.hero__actions { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 48px; }
.hero__stats {
  display: flex;
  gap: 32px;
  flex-wrap: wrap;
}
.hero__stat-value {
  font-size: 28px;
  font-weight: 900;
  color: var(--text);
  line-height: 1;
}
.hero__stat-label { font-size: 13px; color: var(--text-sub); margin-top: 4px; }

/* Phone mockup */
.hero__visual {
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
}
.phone-mockup {
  width: 260px;
  height: 520px;
  border-radius: 44px;
  background: var(--surface);
  border: 8px solid var(--border);
  box-shadow: 0 32px 80px var(--shadow-lg), 0 0 0 1px var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  position: relative;
  transition: background var(--transition), border-color var(--transition);
}
.phone-mockup__notch {
  height: 28px;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-shrink: 0;
  background: var(--surface);
}
.phone-mockup__notch::after {
  content: '';
  width: 80px; height: 12px;
  border-radius: 8px;
  background: var(--border);
}
.phone-screen {
  flex: 1;
  background: var(--bg);
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  overflow: hidden;
}
.phone-screen__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 4px;
}
.phone-screen__title {
  font-size: 15px;
  font-weight: 800;
  color: var(--text);
}
.phone-screen__streak {
  font-size: 12px;
  color: var(--secondary);
  font-weight: 700;
}
.phone-card {
  background: var(--surface);
  border-radius: 10px;
  padding: 12px;
  border: 1px solid var(--border);
}
.phone-question {
  font-size: 22px;
  font-weight: 900;
  color: var(--text);
  text-align: center;
  padding: 16px;
  background: var(--surface);
  border-radius: 10px;
  border: 1px solid var(--border);
  letter-spacing: -0.02em;
}
.phone-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}
.phone-key {
  background: var(--surface-var);
  border-radius: 8px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}
.phone-key--primary { background: var(--primary); color: #fff; }
.phone-bar {
  height: 8px;
  border-radius: 4px;
  background: var(--primary);
  opacity: 0.7;
}
.phone-bar-track {
  height: 8px;
  border-radius: 4px;
  background: var(--surface-var);
  overflow: hidden;
  margin-bottom: 4px;
}
.phone-label { font-size: 11px; color: var(--text-sub); font-weight: 600; margin-bottom: 4px; }

/* floating chips around phone */
.hero__chip {
  position: absolute;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 40px;
  padding: 8px 14px;
  font-size: 12px;
  font-weight: 700;
  color: var(--text);
  box-shadow: 0 4px 16px var(--shadow);
  white-space: nowrap;
  transition: background var(--transition), border-color var(--transition);
}
.hero__chip--1 { top: 60px; right: -20px; }
.hero__chip--2 { bottom: 90px; right: -30px; }
.hero__chip--3 { top: 200px; left: -40px; }

/* ---------- Features ---------- */
.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 56px;
}
.feature-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 28px;
  transition: transform 0.2s, box-shadow 0.2s, background var(--transition), border-color var(--transition);
}
.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 48px var(--shadow-lg);
}
.feature-card__icon {
  font-size: 36px;
  margin-bottom: 16px;
  display: block;
}
.feature-card__title {
  font-size: 17px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 8px;
}
.feature-card__desc {
  font-size: 14px;
  color: var(--text-sub);
  line-height: 1.65;
}

/* ---------- Topics section ---------- */
.topics__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 48px;
}
.topic-chip {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 20px 16px;
  text-align: center;
  transition: transform 0.2s, background var(--transition), border-color var(--transition);
  cursor: default;
}
.topic-chip:hover { transform: translateY(-3px); background: var(--surface-var); }
.topic-chip__icon { font-size: 28px; margin-bottom: 8px; }
.topic-chip__name { font-size: 13px; font-weight: 700; color: var(--text); }

/* ---------- Section headings ---------- */
.section-heading { text-align: center; max-width: 640px; margin: 0 auto; }
.section-heading h2 {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 900;
  letter-spacing: -0.03em;
  color: var(--text);
  margin-bottom: 14px;
  line-height: 1.15;
}
.section-heading p {
  font-size: 17px;
  color: var(--text-sub);
  line-height: 1.7;
}

/* ---------- Pro section ---------- */
.pro-section {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition), border-color var(--transition);
}
.pro__inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 72px;
  align-items: center;
}
.pro__left h2 {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 900;
  letter-spacing: -0.03em;
  color: var(--text);
  margin-bottom: 16px;
  line-height: 1.15;
}
.pro__left p {
  font-size: 16px;
  color: var(--text-sub);
  margin-bottom: 32px;
  line-height: 1.7;
}
.pro__price-row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}
.pro__price-old {
  font-size: 20px;
  color: var(--text-sub);
  text-decoration: line-through;
  opacity: 0.6;
}
.pro__price {
  font-size: 38px;
  font-weight: 900;
  color: var(--primary);
}
.pro__badge {
  background: #E53935;
  color: #fff;
  font-weight: 800;
  font-size: 13px;
  padding: 5px 12px;
  border-radius: 40px;
  letter-spacing: 0.05em;
}
.pro__note { font-size: 13px; color: var(--text-sub); margin-top: 8px; }
.pro__features {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.pro__feature {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px;
  transition: background var(--transition), border-color var(--transition);
}
.pro__feature-icon { font-size: 22px; flex-shrink: 0; }
.pro__feature-title { font-size: 13px; font-weight: 700; color: var(--text); }
.pro__feature-desc { font-size: 12px; color: var(--text-sub); margin-top: 2px; line-height: 1.5; }

/* ---------- Download section ---------- */
.download-section { text-align: center; }
.download__graphic {
  width: 80px; height: 80px;
  background: var(--primary);
  border-radius: 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 40px;
  margin-bottom: 24px;
  box-shadow: 0 8px 32px color-mix(in srgb, var(--primary) 30%, transparent);
}
.download__title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 900;
  letter-spacing: -0.03em;
  color: var(--text);
  margin-bottom: 12px;
}
.download__subtitle {
  font-size: 17px;
  color: var(--text-sub);
  margin-bottom: 36px;
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
}
.download__buttons { display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; margin-bottom: 20px; }
.download__disclaimer { font-size: 13px; color: var(--text-sub); }

/* Play Store badge */
.playstore-btn {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: linear-gradient(135deg, #2c2c2e 0%, #1a1a1c 100%);
  color: #ffffff;
  padding: 14px 28px;
  border-radius: 14px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  transition: opacity 0.2s, transform 0.15s, box-shadow 0.2s;
  border: 1.5px solid rgba(255,255,255,0.10);
  box-shadow: 0 4px 18px rgba(0,0,0,0.22);
}
[data-theme="light"] .playstore-btn {
  background: linear-gradient(135deg, #1e2a3a 0%, #0f1f2e 100%);
  border: 1.5px solid rgba(100,180,255,0.20);
  box-shadow: 0 4px 20px rgba(33,150,243,0.18), 0 2px 8px rgba(0,0,0,0.14);
}
.playstore-btn:hover {
  opacity: 0.92;
  transform: translateY(-3px);
  box-shadow: 0 8px 28px rgba(0,0,0,0.28);
}
[data-theme="light"] .playstore-btn:hover {
  box-shadow: 0 8px 28px rgba(33,150,243,0.28), 0 4px 12px rgba(0,0,0,0.18);
}
.playstore-btn__icon { font-size: 28px; flex-shrink: 0; }
.playstore-btn__text-top { font-size: 11px; font-weight: 400; opacity: 0.75; display: block; line-height: 1; }
.playstore-btn__text-main { font-size: 18px; font-weight: 800; display: block; line-height: 1.2; }

/* ---------- Screenshot Lightbox ---------- */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: rgba(0, 0, 0, 0.88);
  align-items: center;
  justify-content: center;
  padding: 24px;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  animation: lbFadeIn 0.2s ease;
}
.lightbox.open { display: flex; }
@keyframes lbFadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}
.lightbox__img {
  max-height: 90vh;
  max-width: min(420px, 90vw);
  width: auto;
  border-radius: 28px;
  box-shadow: 0 24px 80px rgba(0,0,0,0.75);
  animation: lbPopIn 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes lbPopIn {
  from { transform: scale(0.82); opacity: 0; }
  to   { transform: scale(1);    opacity: 1; }
}
.lightbox__close {
  position: absolute;
  top: 18px;
  right: 22px;
  background: rgba(255,255,255,0.12);
  border: 1.5px solid rgba(255,255,255,0.22);
  color: #fff;
  font-size: 22px;
  line-height: 1;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, transform 0.15s;
}
.lightbox__close:hover { background: rgba(255,255,255,0.25); transform: scale(1.1); }

.lightbox__nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255,255,255,0.12);
  border: 1.5px solid rgba(255,255,255,0.22);
  color: #fff;
  font-size: 28px;
  line-height: 1;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, transform 0.15s;
}
.lightbox__nav:hover { background: rgba(255,255,255,0.25); transform: translateY(-50%) scale(1.1); }
.lightbox__nav--prev { left: 18px; }
.lightbox__nav--next { right: 18px; }
.lightbox__counter {
  position: absolute;
  bottom: 18px;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(255,255,255,0.65);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.05em;
  pointer-events: none;
}

/* Make screenshot frames show pointer to hint they're clickable */
.screenshot-frame { cursor: zoom-in; }

/* ---------- FAQ ---------- */
.faq__list { max-width: 760px; margin: 48px auto 0; }
.faq__item {
  border-bottom: 1px solid var(--border);
  transition: border-color var(--transition);
}
.faq__question {
  width: 100%;
  background: none;
  border: none;
  cursor: pointer;
  text-align: left;
  padding: 20px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  gap: 16px;
}
.faq__chevron {
  font-size: 20px;
  transition: transform 0.3s;
  flex-shrink: 0;
  color: var(--text-sub);
}
.faq__item.open .faq__chevron { transform: rotate(180deg); }
.faq__answer {
  font-size: 15px;
  color: var(--text-sub);
  line-height: 1.75;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
}
.faq__item.open .faq__answer { max-height: 400px; padding-bottom: 20px; }

/* ---------- Footer ---------- */
.footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 56px 0 32px;
  transition: background var(--transition), border-color var(--transition);
}
.footer__inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}
.footer__brand p {
  font-size: 14px;
  color: var(--text-sub);
  margin-top: 12px;
  max-width: 260px;
  line-height: 1.65;
}
.footer__col h4 {
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-sub);
  margin-bottom: 16px;
}
.footer__col ul { list-style: none; }
.footer__col li { margin-bottom: 10px; }
.footer__col a {
  font-size: 14px;
  color: var(--text-sub);
  transition: color var(--transition);
}
.footer__col a:hover { color: var(--primary); opacity: 1; }
.footer__bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-sub);
  flex-wrap: wrap;
  gap: 8px;
}

/* ---------- Privacy / Support page ---------- */
.page-hero {
  padding: 80px 0 60px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  transition: border-color var(--transition);
}
.page-hero h1 {
  font-size: clamp(32px, 5vw, 50px);
  font-weight: 900;
  letter-spacing: -0.03em;
  margin-bottom: 12px;
}
.page-hero p {
  font-size: 17px;
  color: var(--text-sub);
  max-width: 520px;
  margin: 0 auto;
}
.prose {
  max-width: 760px;
  margin: 0 auto;
  padding: 64px 24px;
}
.prose h2 {
  font-size: 22px;
  font-weight: 800;
  color: var(--text);
  margin-top: 40px;
  margin-bottom: 12px;
}
.prose h3 {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin-top: 24px;
  margin-bottom: 8px;
}
.prose p {
  font-size: 15px;
  color: var(--text-sub);
  margin-bottom: 16px;
  line-height: 1.8;
}
.prose ul, .prose ol {
  margin: 12px 0 20px 24px;
}
.prose li {
  font-size: 15px;
  color: var(--text-sub);
  margin-bottom: 8px;
  line-height: 1.75;
}
.prose strong { color: var(--text); font-weight: 700; }
.prose a { color: var(--primary); }
.prose .last-updated {
  display: inline-block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 40px;
  padding: 6px 16px;
  font-size: 13px;
  color: var(--text-sub);
  margin-bottom: 32px;
}
.info-box {
  background: color-mix(in srgb, var(--primary) 8%, transparent);
  border: 1px solid color-mix(in srgb, var(--primary) 25%, transparent);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  margin: 20px 0;
  font-size: 14px;
  color: var(--text);
  line-height: 1.65;
}

/* Contact card */
.contact-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px;
  text-align: center;
  max-width: 480px;
  margin: 48px auto 0;
  transition: background var(--transition), border-color var(--transition);
}
.contact-card h3 { font-size: 20px; font-weight: 800; margin-bottom: 10px; }
.contact-card p { font-size: 15px; color: var(--text-sub); margin-bottom: 24px; }
.contact-card__email {
  font-size: 17px;
  font-weight: 700;
  color: var(--primary);
  display: block;
  margin-bottom: 20px;
}

/* ---------- Scroll animations ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: none;
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero__inner  { grid-template-columns: 1fr; }
  .hero__visual { display: none; }
  .features__grid { grid-template-columns: 1fr 1fr; }
  .topics__grid   { grid-template-columns: repeat(3, 1fr); }
  .pro__inner     { grid-template-columns: 1fr; gap: 40px; }
  .footer__inner  { grid-template-columns: 1fr 1fr; gap: 32px; }
}

@media (max-width: 640px) {
  .section { padding: 64px 0; }
  .features__grid { grid-template-columns: 1fr; }
  .topics__grid   { grid-template-columns: 1fr 1fr; }
  .pro__features  { grid-template-columns: 1fr; }
  .footer__inner  { grid-template-columns: 1fr; }
  .navbar__links  { display: none; }
  .menu-toggle    { display: flex; }
  .navbar--open .navbar__links {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: var(--navbar-h);
    left: 0; right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 24px;
    gap: 20px;
    z-index: 99;
  }
  .footer__bottom { flex-direction: column; text-align: center; }
}

/* ---------- Screenshot Carousel ---------- */
.screenshots-section {
  padding: 96px 0;
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition), border-color var(--transition);
  overflow: hidden;
}

.carousel {
  display: flex;
  align-items: center;
  gap: 12px;
  max-width: 1120px;
  margin: 0 auto;
  padding: 12px 24px 4px;
}

.carousel__viewport {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  border-radius: 4px;
}

.carousel__track {
  display: flex;
  gap: 18px;
  transition: transform 0.45s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  will-change: transform;
}

.carousel__btn {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 2px solid var(--border);
  background: var(--card);
  color: var(--text);
  font-size: 26px;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), border-color var(--transition),
              opacity var(--transition), transform 0.15s;
  box-shadow: 0 2px 10px var(--shadow);
}
.carousel__btn:hover:not(:disabled) {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  transform: scale(1.08);
}
.carousel__btn:disabled {
  opacity: 0.25;
  cursor: default;
}

.screenshot-frame {
  flex: 0 0 auto;
  width: 190px;
  border-radius: 22px;
  overflow: hidden;
  box-shadow: 0 10px 36px var(--shadow-lg);
  border: 2px solid var(--border);
  background: var(--card);
  transition: transform var(--transition), box-shadow var(--transition);
}
.screenshot-frame:hover {
  transform: translateY(-6px);
  box-shadow: 0 18px 48px var(--shadow-lg);
}
.screenshot-frame img {
  width: 100%;
  height: auto;
  display: block;
}

.carousel__dots {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 20px;
  padding: 0 24px;
}
.carousel__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--border);
  border: none;
  padding: 0;
  cursor: pointer;
  transition: background var(--transition), transform 0.15s;
}
.carousel__dot--active {
  background: var(--primary);
  transform: scale(1.35);
}

@media (max-width: 640px) {
  .screenshot-frame { width: 150px; }
  .carousel__btn { width: 36px; height: 36px; font-size: 22px; }
  .screenshots-section { padding: 64px 0; }
  .carousel { gap: 8px; padding: 12px 12px 4px; }
  .carousel__track { gap: 12px; }
}