@import url("https://fonts.googleapis.com/css2?family=Inter:opsz,wght@14..32,100..900&display=swap");

:root {
  --background: #f6f6f6;
  --surface: #ffffff;
  --accent: #0b0b0b;
  --body: #5a5a5a;
  --sub: #7c7c7c;
  --line: #e2e2e2;
  --highlight: #dadada;
  --brand: #12935a;
  --brand-soft: rgba(18, 147, 90, 0.12);
  --ok: #1f9d55;
  --bad: #d0453a;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 8px 24px rgba(0, 0, 0, 0.06);
  color: var(--body);
  color-scheme: light dark;
  font-family: Inter, "SF Pro", ui-sans-serif, sans-serif;
  font-weight: 450;
  line-height: 1.45;
  letter-spacing: -0.2px;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #000;
    --surface: #0f0f0f;
    --accent: #ededed;
    --body: #a2a2a2;
    --sub: #6e6e6e;
    --line: #222;
    --highlight: #262626;
    --brand: #2fc27d;
    --brand-soft: rgba(47, 194, 125, 0.14);
    --shadow: none;
  }
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
::selection { background: var(--highlight); }
html { background: var(--background); scroll-behavior: smooth; scroll-padding-top: 72px; }
body { margin: 0; background: var(--background); }

.wrap { width: 100%; max-width: 1080px; margin: 0 auto; padding-left: 20px; padding-right: 20px; }

h1, h2, h3, h4 { color: var(--accent); margin: 0; letter-spacing: -0.6px; line-height: 1.15; }
h1 { font-size: clamp(34px, 6vw, 56px); font-weight: 700; letter-spacing: -1.6px; }
h2 { font-size: clamp(26px, 4vw, 36px); font-weight: 680; letter-spacing: -1px; }
h3 { font-size: 18px; font-weight: 620; }
h4 { font-size: 16px; font-weight: 600; margin: 20px 0 8px; }
p { margin: 0; }
a { color: inherit; text-underline-offset: 2px; }
.accent { color: var(--brand); }
.muted { color: var(--sub); font-size: 14px; }

/* nav */
.nav { position: sticky; top: 0; z-index: 10; background: color-mix(in srgb, var(--background) 82%, transparent); backdrop-filter: blur(12px); border-bottom: 1px solid var(--line); }
.nav-inner { display: flex; align-items: center; gap: 24px; height: 60px; }
.brand { display: flex; align-items: center; gap: 8px; text-decoration: none; color: var(--accent); font-weight: 650; font-size: 17px; }
.brand b { color: var(--brand); font-weight: 650; }
.globe-icon { width: 28px; height: 28px; cursor: grab; touch-action: none; user-select: none; }
.nav-links { display: flex; gap: 20px; margin-left: auto; font-size: 15px; }
.nav-links a { text-decoration: none; }
.nav-links a:hover { color: var(--accent); }

/* buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 6px; font: inherit; font-size: 15px; font-weight: 550; color: var(--accent); background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 9px 16px; cursor: pointer; text-decoration: none; transition: transform 0.1s, background 0.15s; }
.btn:hover { background: var(--highlight); }
.btn:active { transform: scale(0.98); }
.btn.primary { background: var(--brand); border-color: var(--brand); color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }
.btn.big { padding: 13px 22px; font-size: 16px; border-radius: 12px; }
.small-btn { font-size: 14px; padding: 7px 12px; }
.link-btn { font: inherit; font-size: 14px; color: var(--sub); background: none; border: 0; padding: 0; margin-top: 16px; cursor: pointer; text-decoration: underline; text-underline-offset: 2px; }
button:focus-visible, a:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }

/* hero */
.hero { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: center; padding-top: 72px; padding-bottom: 40px; }
.badge { display: inline-block; font-size: 13px; font-weight: 550; color: var(--brand); background: var(--brand-soft); border-radius: 999px; padding: 4px 12px; margin-bottom: 18px; }
.lead { font-size: 18px; margin: 18px 0 28px; max-width: 540px; }
.actions { display: flex; gap: 10px; flex-wrap: wrap; }
.numbers { display: flex; gap: 32px; margin-top: 36px; flex-wrap: wrap; }
.numbers strong { display: block; color: var(--accent); font-size: 30px; font-weight: 700; letter-spacing: -1px; }
.numbers span { font-size: 14px; color: var(--sub); }

.hero-card { background: var(--surface); border: 1px solid var(--line); border-radius: 20px; padding: 22px; box-shadow: var(--shadow); transform: rotate(1.2deg); }
.mock-head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 4px; }

/* sections */
.section { padding-top: 72px; padding-bottom: 8px; }
.section-lead { font-size: 17px; margin: 10px 0 28px; max-width: 620px; }

.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.feature { background: var(--surface); border: 1px solid var(--line); border-radius: 16px; padding: 20px; }
.feature .icon { font-size: 24px; display: block; margin-bottom: 12px; }
.feature p { font-size: 15px; margin-top: 6px; }

/* trainer app */
.app { background: var(--surface); border: 1px solid var(--line); border-radius: 20px; box-shadow: var(--shadow); overflow: hidden; }
.tabs { display: flex; gap: 4px; padding: 8px; border-bottom: 1px solid var(--line); overflow-x: auto; scrollbar-width: none; }
.tabs button { font: inherit; font-size: 15px; font-weight: 550; color: var(--sub); background: none; border: 0; border-radius: 10px; padding: 9px 14px; cursor: pointer; white-space: nowrap; }
.tabs button:hover { color: var(--accent); }
.tabs button[aria-selected="true"] { color: var(--accent); background: var(--highlight); }
.app-view { padding: 24px; min-height: 420px; }

.view-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 16px; flex-wrap: wrap; }
.topic-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 10px; }
.topic-card { font: inherit; text-align: left; color: var(--body); background: var(--background); border: 1px solid var(--line); border-radius: 14px; padding: 16px; cursor: pointer; display: grid; gap: 6px; transition: border-color 0.15s, transform 0.1s; }
.topic-card:hover { border-color: var(--brand); }
.topic-card:active { transform: scale(0.99); }
.topic-card strong { color: var(--accent); font-weight: 600; }

.bar { height: 6px; border-radius: 99px; background: var(--highlight); overflow: hidden; }
.bar span { display: block; height: 100%; background: var(--brand); border-radius: inherit; transition: width 0.3s; }

.center-box { max-width: 460px; margin: 48px auto; text-align: center; display: grid; gap: 14px; justify-items: center; }

.session-head { display: flex; align-items: center; gap: 12px; margin-bottom: 10px; }
.session-head strong { color: var(--accent); }
.clock { margin-left: auto; font-variant-numeric: tabular-nums; font-weight: 600; color: var(--accent); }
.session-body { margin-top: 20px; max-width: 680px; }

.chip { display: inline-block; font-size: 12px; font-weight: 550; color: var(--brand); background: var(--brand-soft); border-radius: 999px; padding: 3px 10px; }
.question { color: var(--accent); font-size: 19px; font-weight: 560; margin: 12px 0 16px; letter-spacing: -0.3px; }
.options { display: grid; gap: 8px; margin-bottom: 14px; }
.option { font: inherit; font-size: 15px; display: flex; align-items: center; gap: 12px; text-align: left; color: var(--accent); background: var(--background); border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; cursor: pointer; transition: border-color 0.15s; }
.option:not(:disabled):hover { border-color: var(--sub); }
.option:disabled { cursor: default; }
.option kbd { font: inherit; font-size: 12px; color: var(--sub); border: 1px solid var(--line); border-radius: 6px; min-width: 22px; text-align: center; padding: 1px 4px; }
.option.correct { border-color: var(--ok); background: rgba(31, 157, 85, 0.12); }
.option.wrong { border-color: var(--bad); background: rgba(208, 69, 58, 0.12); }
.option.picked { border-color: var(--accent); }

.why { display: grid; gap: 2px; font-size: 15px; border-radius: 12px; padding: 12px 14px; margin-bottom: 14px; }
.why.ok { background: rgba(31, 157, 85, 0.1); }
.why.bad { background: rgba(208, 69, 58, 0.1); }
.why.ok strong, .ok-text { color: var(--ok); }
.why.bad strong, .bad-text { color: var(--bad); }

.result { display: grid; gap: 4px; padding: 20px; border-radius: 14px; background: var(--background); border: 1px solid var(--line); }
.result strong { color: var(--accent); font-size: 32px; letter-spacing: -1px; }
.result.ok { border-color: var(--ok); }
.result.bad { border-color: var(--bad); }
.review { display: grid; gap: 4px; font-size: 14px; padding: 12px 0; border-bottom: 1px solid var(--line); }
.review strong { color: var(--accent); font-weight: 550; font-size: 15px; }
.session-body > .actions { margin-top: 20px; }

.tiles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin: 16px 0 24px; }
.tile { background: var(--background); border: 1px solid var(--line); border-radius: 14px; padding: 16px; display: grid; gap: 2px; }
.tile strong { color: var(--accent); font-size: 28px; letter-spacing: -1px; }
.topic-bars { display: grid; gap: 12px; max-width: 640px; }
.topic-row { display: grid; grid-template-columns: 220px 1fr 44px; gap: 12px; align-items: center; font-size: 15px; }
.topic-row .muted { text-align: right; }

/* signs */
.sign-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 12px; }
.sign-card { font: inherit; position: relative; aspect-ratio: 3 / 4; padding: 0; color: var(--body); background: var(--surface); border: 1px solid var(--line); border-radius: 16px; cursor: pointer; perspective: 800px; transition: border-color 0.15s; }
.sign-card:hover { border-color: var(--brand); }
.sign-front, .sign-back { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 12px; padding: 14px; text-align: center; backface-visibility: hidden; transition: transform 0.45s; }
.sign-front svg { width: 64%; height: auto; }
.sign-front strong, .sign-back strong { color: var(--accent); font-size: 14px; font-weight: 600; line-height: 1.25; }
.sign-back { transform: rotateY(180deg); font-size: 14px; }
.sign-card.flipped .sign-front { transform: rotateY(-180deg); }
.sign-card.flipped .sign-back { transform: rotateY(0); }

/* steps, faq, cta */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 28px; }
.step b { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; background: var(--brand-soft); color: var(--brand); margin-bottom: 12px; }
.step p { font-size: 15px; margin-top: 6px; }

.faq { display: grid; gap: 8px; margin-top: 24px; max-width: 760px; }
.faq details { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 14px 18px; }
.faq summary { color: var(--accent); font-weight: 560; cursor: pointer; list-style: none; display: flex; justify-content: space-between; }
.faq summary::after { content: "+"; color: var(--sub); font-size: 20px; line-height: 1; }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin-top: 8px; font-size: 15px; }

.cta { text-align: center; padding-bottom: 72px; }
.cta p { font-size: 17px; margin: 10px 0 24px; }

.footer { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; font-size: 14px; color: var(--sub); border-top: 1px solid var(--line); padding-top: 24px; padding-bottom: 32px; }

/* responsive */
@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; padding-top: 48px; }
  .hero-card { transform: none; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .sign-grid { grid-template-columns: repeat(3, 1fr); }
}
@media (max-width: 640px) {
  .wrap { padding-left: 16px; padding-right: 16px; }
  .nav-links { display: none; }
  .nav-cta { margin-left: auto; }
  .feature-grid, .steps { grid-template-columns: 1fr; }
  .sign-grid { grid-template-columns: repeat(2, 1fr); }
  .tiles { grid-template-columns: 1fr; }
  .topic-row { grid-template-columns: 1fr 44px; }
  .topic-row .bar { grid-column: 1 / -1; grid-row: 2; }
  .app-view { padding: 16px; }
  .section { padding-top: 56px; }
}