/* Landing layout: header, hero, sections, footer, responsive */

/* ---------- Header ---------- */
.site-header { position: sticky; top: 0; z-index: 40; height: 76px; transition: background var(--dur-fast) var(--ease), box-shadow var(--dur-fast) var(--ease); }
.site-header.is-scrolled { background: rgba(251, 247, 239, .92); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); box-shadow: 0 1px 0 var(--color-line); }
.site-header__inner { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: var(--space-5); }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; }
.brand__mark { display: block; width: auto; height: 34px; }
.brand__word { display: block; width: auto; height: 30px; }
.brand--small .brand__mark { height: 26px; }
.brand--small .brand__word { height: 23px; }
.site-nav { display: flex; gap: 28px; margin-left: auto; }
.site-nav a { font: 500 15px/1 var(--font-body); color: var(--color-ink-2); text-decoration: none; padding: 8px 0; }
.site-nav a:hover { color: var(--color-pine); }
.lang-switch { display: flex; padding: 3px; border-radius: 10px; background: var(--color-mint-label); }
.lang-switch__btn { min-width: 44px; height: 38px; border: 0; border-radius: 8px; background: transparent; cursor: pointer; font: 600 12px/1 var(--font-mono); color: var(--color-pine); }
.lang-switch__btn[aria-pressed="true"] { background: var(--color-white); color: var(--color-ink); box-shadow: 0 1px 2px rgba(0, 0, 0, .08); }

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; margin-top: -76px; padding: 130px 0 72px; min-height: 100vh; }
.hero::before { content: ""; position: absolute; right: -6%; top: 6%; width: 760px; height: 760px; border-radius: 50%; background: radial-gradient(closest-side, rgba(214, 236, 221, .95), rgba(214, 236, 221, 0)); pointer-events: none; }
.hero__remember {
  position: absolute; left: 0; right: 0; top: 64%; z-index: 0;
  text-align: center; white-space: nowrap; pointer-events: none; user-select: none;
  font: 700 clamp(96px, 17vw, 250px)/1 var(--font-heading); letter-spacing: -.03em;
  color: var(--color-remember);
}
.hero__remember span { display: inline-block; transition: color var(--dur-slow) var(--ease), transform var(--dur-slow) var(--ease); }
.hero__remember span.is-lit { color: #C5E2CD; transform: translateY(-4px); }
.hero__grid {
  position: relative; z-index: 1;
  display: grid; grid-template-columns: minmax(0, 1fr) auto;
  grid-template-areas: "copy phone" "cta phone";
  grid-template-rows: auto 1fr; column-gap: 96px; align-items: start;
}
.hero__copy { grid-area: copy; padding-top: 48px; display: flex; flex-direction: column; align-items: flex-start; gap: 24px; max-width: 580px; }
.hero__title { font-size: var(--h1); line-height: 1.02; letter-spacing: -.035em; }
.hero__title span { display: block; white-space: nowrap; }
.hero__title-accent { color: var(--color-pine); }
.hero__lead { max-width: 440px; font-size: var(--lead); line-height: 1.55; color: var(--color-ink-2); }
.hero__features { display: flex; flex-wrap: wrap; gap: 10px 22px; }
.hero__features li { display: flex; align-items: center; gap: 8px; font: 500 14px/1 var(--font-body); color: var(--color-muted); }
.hero__features svg { width: 16px; height: 16px; fill: none; stroke: var(--color-pine); stroke-width: 2; stroke-linecap: round; }
.hero__cta { grid-area: cta; padding-top: 28px; }
.hero__phone { grid-area: phone; position: relative; width: 440px; display: flex; flex-direction: column; align-items: center; gap: 18px; padding-top: 24px; }

.progress-chip {
  position: absolute; right: calc(100% + 40px); top: 54%;
  width: 184px; padding: 12px 14px; display: flex; flex-direction: column; gap: 8px;
  background: var(--color-white); border: 1px solid var(--color-line); border-radius: var(--radius-m); box-shadow: var(--shadow-float);
}
.progress-chip__label { font: 500 10px/1.2 var(--font-mono); letter-spacing: .06em; text-transform: uppercase; color: var(--color-muted); }
.progress-chip__bars { display: flex; gap: 4px; }
.progress-chip__bars i { flex: 1; height: 4px; border-radius: 2px; background: var(--color-mint); }
.progress-chip__bars i.is-on { background: var(--color-pine); }

/* Demo controls under the phone */
.demo-controls { display: flex; align-items: center; gap: 10px 14px; flex-wrap: wrap; justify-content: center; max-width: 100%; }
.demo-btn {
  display: inline-flex; align-items: center; gap: 9px; min-height: 44px; padding: 0 18px 0 14px;
  border-radius: var(--radius-pill); border: 1px solid var(--color-line); background: var(--color-white);
  color: var(--color-ink); cursor: pointer; font: 600 14px/1 var(--font-body);
  box-shadow: 0 6px 18px -12px rgba(19, 38, 29, .35);
}
.demo-btn:hover { border-color: rgba(30, 59, 46, .35); }
.demo-btn[aria-disabled="true"] { opacity: .55; cursor: default; }
.demo-btn__icon { width: 16px; height: 16px; fill: var(--color-pine); }
.demo-btn__icon--replay { display: none; fill: none; stroke: var(--color-pine); stroke-width: 2.2; stroke-linecap: round; }
.demo-btn.is-replay .demo-btn__icon--play { display: none; }
.demo-btn.is-replay .demo-btn__icon--replay { display: block; }
.demo-hint { font: 500 14px/1.3 var(--font-body); color: var(--color-muted); }
.demo-progress { width: 120px; height: 4px; border-radius: 2px; background: var(--color-mint); overflow: hidden; }
.demo-progress__bar { display: block; height: 100%; width: 0; background: var(--color-pine); }
.demo-progress__bar.is-running { animation: demo-progress var(--demo-length) linear forwards; }
.demo-progress__bar.is-done { width: 100%; }
@keyframes demo-progress { from { width: 0; } to { width: 100%; } }

/* ---------- Sections ---------- */
.section { position: relative; padding: var(--space-10) 0; }
.section__title { font-size: var(--h2); line-height: 1.05; letter-spacing: -.03em; max-width: 760px; }
.section__lead { margin-top: var(--space-5); max-width: 620px; font-size: var(--lead); line-height: 1.55; color: var(--color-ink-2); }
.step__num { display: inline-flex; align-items: center; justify-content: center; width: 32px; height: 32px; border-radius: 50%; background: var(--color-ink); color: var(--color-cream); font: 500 13px/1 var(--font-mono); }

/* How tuvedu works */
.steps { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: var(--space-5); margin-top: var(--space-8); }
.step { display: flex; flex-direction: column; gap: 12px; padding: 24px; background: var(--color-white); border: 1px solid var(--color-line); border-radius: var(--radius-l); }
.step__title { font-size: 22px; letter-spacing: -.02em; }
/* RU only: "Потренироваться" is the longest word in the four cards. In the
   four-column layout (1025 px and up) it scales down with the viewport until
   the card is wide enough, then stays at 22 px like the other headings. */
@media (min-width: 1025px) {
  html[lang="ru"] .step__title--long-ru { font-size: clamp(17px, 1.7vw, 22px); }
}
.step__text { font-size: 15px; line-height: 1.5; color: var(--color-ink-2); min-height: 68px; }
.frag { margin-top: auto; display: flex; flex-direction: column; gap: 8px; padding: 14px; min-height: 112px; border-radius: 14px; background: var(--app-bg); font-family: var(--app-font); }
.frag__line { height: 7px; border-radius: 4px; background: rgba(0, 0, 0, .12); }
.frag__line.w80 { width: 80%; } .frag__line.w60 { width: 60%; }
.frag__why { font: 700 10px/1 var(--app-font); letter-spacing: .1em; color: var(--app-subject); }
.frag__example { height: 30px; border-radius: 10px; background: var(--app-subject-tint); }
.frag__field { height: 42px; border-radius: 10px; background: var(--app-card); }
.frag__mic { width: 30px; height: 30px; border-radius: 50%; background: var(--app-green); }
.frag__pill { display: flex; align-items: center; gap: 4px; height: 26px; padding: 0 10px; border-radius: 13px; background: var(--app-fill); }
.frag__pill i, .meter i { display: block; width: 7px; height: 7px; border-radius: 50%; background: var(--app-green); }
.frag__pill i.ring, .meter i.ring { background: transparent; border: 2px solid var(--app-amber); }
.frag__verdict { font: 700 14px/1 var(--app-font); color: var(--app-ok); }
.frag__kicker { font: 600 9px/1 var(--app-font); letter-spacing: .1em; color: var(--app-subject); }

/* Learn anything */
.learn__head { display: flex; justify-content: space-between; align-items: flex-end; gap: var(--space-7); }
.topic-chips { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 10px; max-width: 460px; }
.topic-chips li { padding: 11px 16px; border-radius: var(--radius-pill); background: var(--color-mint); color: var(--color-pine); font: 600 14px/1 var(--font-body); }
.topic-chips li.is-active { background: var(--color-pine); color: var(--color-cream); }
.flow { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: var(--space-4); margin-top: var(--space-8); counter-reset: flow; }
.flow__step { display: flex; flex-direction: column; gap: 10px; padding: 22px; background: var(--color-white); border: 1px solid var(--color-line); border-radius: var(--radius-l); }
.flow__step h3 { font-size: 18px; letter-spacing: -.01em; }
.flow__step p { font-size: 14px; line-height: 1.5; }
.learn__note { margin-top: var(--space-5); max-width: 720px; font: 500 14px/1.5 var(--font-body); color: var(--color-muted); }

/* Meet Buddy (the one dark block) */
.section--dark { background: var(--color-pine-deep); color: #C9D6CC; }
.section--dark .section__title { color: #EDF3EA; }
.section--dark .section__lead { color: #C9D6CC; }
.buddy { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: var(--space-8); align-items: center; }
.buddy__facts { margin-top: var(--space-6); display: flex; flex-direction: column; gap: 12px; }
.buddy__facts li { padding-left: 22px; position: relative; color: #EDF3EA; font-size: 16px; }
.buddy__facts li::before { content: ""; position: absolute; left: 0; top: .55em; width: 8px; height: 8px; border-radius: 50%; background: var(--color-signal-mint); }
.buddy__visual { display: flex; flex-direction: column; align-items: center; gap: 28px; padding: 48px 24px; border-radius: 28px; background: radial-gradient(closest-side, rgba(62, 138, 99, .45), rgba(19, 38, 29, 0)); }
.meter { display: flex; align-items: center; gap: 14px; height: 64px; }
.meter i { width: 26px; height: 26px; background: var(--color-signal-mint); }
.meter i.ring { border-width: 5px; }
.meter i:nth-child(1) { animation: meter 1.1s ease-in-out infinite; }
.meter i:nth-child(2) { animation: meter 1.1s ease-in-out .18s infinite; }
.meter i:nth-child(3) { animation: meter 1.1s ease-in-out .36s infinite; }
@keyframes meter { 0%, 100% { height: 26px; } 50% { height: 60px; border-radius: 13px; } }
.buddy__states { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; }
.buddy__states span { padding: 9px 14px; border-radius: var(--radius-pill); box-shadow: inset 0 0 0 1px rgba(220, 238, 223, .28); font: 500 12px/1 var(--font-mono); color: #C9D6CC; }
.buddy__states span.is-on { background: var(--color-signal-mint); color: var(--color-ink); box-shadow: none; }
.buddy__mic { width: 84px; height: 84px; border-radius: 50%; background: var(--app-red); box-shadow: 0 0 0 12px rgba(224, 53, 43, .18); display: flex; align-items: center; justify-content: center; }
.buddy__mic span { width: 26px; height: 26px; border-radius: 50%; background: var(--color-white); }

/* Learn that lasts */
.lasts { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr); gap: var(--space-8); align-items: center; }
.lasts__frags { display: grid; gap: var(--space-4); }
.lfrag { display: flex; flex-direction: column; gap: 8px; padding: 18px 20px; border-radius: 18px; background: var(--app-card); box-shadow: 0 10px 28px -16px rgba(0, 0, 0, .25); font-family: var(--app-font); color: var(--app-text); }
.lfrag__kicker { font: 600 11px/1 var(--app-font); letter-spacing: .1em; text-transform: uppercase; color: var(--app-grey-2); }
.lfrag__kicker--subject { color: var(--app-subject); }
.lfrag__title { font: 700 19px/1.2 var(--app-font); }
.lfrag__text { font: 400 15px/1.4 var(--app-font); color: var(--app-grey-2); }
.lfrag__bars { display: flex; gap: 5px; }
.lfrag__bars i { flex: 1; height: 5px; border-radius: 3px; background: var(--app-fill); }
.lfrag__bars i.is-on { background: var(--app-subject); }
.lfrag__btn { align-self: flex-start; padding: 14px 20px; border-radius: 26px; background: var(--app-green); color: #fff; font: 600 15px/1 var(--app-font); }

/* Final CTA */
.section--cta { padding-top: var(--space-9); }
.final-cta { display: flex; flex-direction: column; align-items: center; gap: var(--space-5); text-align: center; }
.final-cta .section__title { margin: 0 auto; }

/* Footer */
.site-footer { border-top: 1px solid var(--color-line); padding: 28px 0; }
.site-footer__inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.site-footer__note { font: 500 13px/1.3 var(--font-body); color: var(--color-muted); }

/* Reveal on scroll */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity var(--dur-slow) var(--ease), transform var(--dur-slow) var(--ease); }
.reveal.is-visible { opacity: 1; transform: none; }
.no-js .reveal { opacity: 1; transform: none; }

/* ---------- Responsive ---------- */
@media (max-width: 1280px) {
  :root { --gutter: 56px; --device-scale: .76; }
  .hero__grid { column-gap: 64px; }
}
@media (max-width: 1180px) {
  .progress-chip { display: none; }   /* never squeezed against the phone */
  .site-nav { gap: 20px; }
}
@media (max-height: 940px) and (min-width: 861px) {
  :root { --device-scale: .72; }
  .hero { padding-top: 108px; padding-bottom: 40px; }
  .hero__phone { padding-top: 0; gap: 14px; }
}
@media (max-height: 800px) and (min-width: 861px) {
  :root { --device-scale: .64; }
}
@media (max-width: 1024px) {
  .site-nav { display: none; }
  .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .flow { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .learn__head { flex-direction: column; align-items: flex-start; }
  .topic-chips { justify-content: flex-start; }
}
@media (max-width: 860px) {
  .hero__phone { width: auto; }
  :root { --gutter: 20px; --device-scale: .8; }
  .hero { min-height: 0; padding: 104px 0 48px; }
  .hero__grid { grid-template-columns: minmax(0, 1fr); grid-template-areas: "copy" "phone" "cta"; row-gap: 32px; }
  .hero__copy { padding-top: 0; gap: 16px; }
  .hero__features { display: none; }
  .hero__remember { top: auto; bottom: 34%; font-size: 19vw; }
  .hero__cta .btn { width: 100%; justify-content: center; }
  .hero__cta { padding-top: 0; }
  .buddy, .lasts { grid-template-columns: minmax(0, 1fr); }
  .section { padding: var(--space-9) 0; }
}
@media (max-width: 640px) {
  .steps, .flow { grid-template-columns: minmax(0, 1fr); }
  .step__text { min-height: 0; }
  .site-footer__inner { flex-direction: column; align-items: flex-start; }
}
@media (max-width: 400px) {
  :root { --device-scale: .74; }
}