/* CS Tutorials — the front door.
 *
 * One screen, one action. The picture carries the warmth, the type carries the
 * promise, and the only thing to press is Open. Everything below the fold is
 * three short answers for somebody who wants them before they walk in.
 *
 * Scale: 11 · 12 · 14 · 16 · 19 · 28 · 44 · 64   Spacing: 4 · 8 · 12 · 16 · 24 · 32 · 48 · 72
 */

:root {
  --bg:      #081120;
  --bg-2:    #0b1526;
  --ink:     #f2f6fb;
  --ink-2:   #b6c6da;
  --ink-3:   #8497b1;
  --gold:    #d4af37;
  --gold-2:  #f0d27a;
  --go:      #e8892f;
  --line:    rgba(212, 175, 55, .22);
  --ease:    cubic-bezier(.2, .7, .3, 1);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  color: var(--ink);
  background:
    radial-gradient(900px 700px at 78% -10%, #14304f 0%, transparent 62%),
    radial-gradient(700px 500px at 8% 110%, #12233b 0%, transparent 60%),
    linear-gradient(180deg, var(--bg-2) 0%, var(--bg) 100%);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.page {
  max-width: 1180px;
  margin: 0 auto;
  padding: 28px 20px 40px;
}

/* ------------------------------------------------------------------ brand */
.brand {
  display: flex; align-items: center; gap: 12px;
  margin-bottom: 34px;
  animation: rise 520ms var(--ease) both;
}
.brand__mark {
  width: 40px; height: 40px; border-radius: 12px;
  display: grid; place-items: center;
  border: 1.5px solid var(--gold);
  color: var(--gold-2); font-weight: 800; font-size: 13px; letter-spacing: .02em;
  background: rgba(212, 175, 55, .06);
}
.brand__word {
  font-size: 13px; font-weight: 650; letter-spacing: .16em; text-transform: uppercase;
  color: var(--ink-2);
}

/* ------------------------------------------------------------------- hero */
.hero {
  display: grid;
  gap: 26px;
  align-items: center;
}

.hero__art {
  position: relative;
  order: 1;
  border-radius: 20px;
  overflow: hidden;
  border: 1px solid rgba(212, 175, 55, .16);
  box-shadow:
    0 30px 70px -30px rgba(0, 0, 0, .9),
    0 0 0 1px rgba(255, 255, 255, .02) inset;
  animation: rise 640ms var(--ease) 80ms both;
}
.hero__art img {
  display: block; width: 100%; height: auto;
  /* the illustration is already dark; this keeps the left edge melting into the page */
  -webkit-mask-image: linear-gradient(100deg, transparent 0%, #000 14%, #000 100%);
          mask-image: linear-gradient(100deg, transparent 0%, #000 14%, #000 100%);
}
.hero__art::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(8, 17, 32, 0) 55%, rgba(8, 17, 32, .55) 100%);
  pointer-events: none;
}

.hero__text { order: 2; }

.kicker {
  margin: 0 0 14px;
  font-size: 11px; font-weight: 600; letter-spacing: .18em; text-transform: uppercase;
  color: var(--gold);
  animation: rise 560ms var(--ease) 120ms both;
}

h1 {
  margin: 0;
  font-size: clamp(44px, 11vw, 76px);
  line-height: .98;
  letter-spacing: -.035em;
  font-weight: 620;
  animation: rise 600ms var(--ease) 160ms both;
}

.lede {
  margin: 18px 0 0;
  max-width: 34ch;
  font-size: 17px;
  line-height: 1.55;
  color: var(--ink-2);
  animation: rise 600ms var(--ease) 220ms both;
}

/* ------------------------------------------------------------------- open */
.open {
  display: inline-flex; align-items: center; gap: 12px;
  margin-top: 30px;
  padding: 17px 30px 17px 34px;
  border-radius: 999px;
  background: linear-gradient(180deg, #f2d888, var(--gold) 62%, #c39f2c);
  color: #221905;
  font-size: 19px; font-weight: 700; letter-spacing: -.01em;
  text-decoration: none;
  box-shadow: 0 16px 34px -14px rgba(212, 175, 55, .6), 0 1px 0 rgba(255, 255, 255, .35) inset;
  transition: transform 160ms var(--ease), box-shadow 200ms var(--ease), filter 160ms var(--ease);
  animation: rise 620ms var(--ease) 280ms both;
}
.open svg { transition: transform 200ms var(--ease); }
.open:hover { filter: brightness(1.04); box-shadow: 0 20px 40px -14px rgba(212, 175, 55, .72), 0 1px 0 rgba(255, 255, 255, .4) inset; }
.open:hover svg { transform: translateX(4px); }
.open:active { transform: translateY(1px) scale(.995); }
.open:focus-visible { outline: none; box-shadow: 0 0 0 3px var(--bg), 0 0 0 6px rgba(212, 175, 55, .6); }

.reassure {
  margin: 14px 0 0;
  font-size: 13px; color: var(--ink-3);
  animation: rise 640ms var(--ease) 320ms both;
}

.install-line { margin: 18px 0 0; }
.ghost {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 9px 14px;
  border: 1px solid rgba(255, 255, 255, .12);
  border-radius: 999px;
  background: transparent; color: var(--ink-2);
  font: inherit; font-size: 12.5px; font-weight: 600;
  cursor: pointer;
  transition: background 160ms var(--ease), color 160ms var(--ease), border-color 160ms var(--ease);
}
.ghost:hover { background: rgba(255, 255, 255, .05); color: var(--ink); border-color: rgba(255, 255, 255, .2); }
.ghost:focus-visible { outline: none; box-shadow: 0 0 0 2px var(--bg), 0 0 0 4px rgba(212, 175, 55, .55); }

/* ------------------------------------------------------------------ facts */
.facts {
  display: grid; gap: 18px;
  margin: 56px 0 0; padding: 28px 0 0;
  list-style: none;
  border-top: 1px solid rgba(255, 255, 255, .07);
}
.facts h2 {
  margin: 0 0 6px;
  font-size: 12px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase;
  color: var(--gold-2);
}
.facts p { margin: 0; font-size: 14.5px; line-height: 1.55; color: var(--ink-2); max-width: 34ch; }

/* ------------------------------------------------------------------- foot */
.foot {
  margin-top: 40px; padding-top: 18px;
  border-top: 1px solid rgba(255, 255, 255, .07);
  font-size: 12.5px; line-height: 1.9; color: var(--ink-3);
}
.foot p { margin: 0; }
.foot a { color: var(--ink-2); text-decoration: none; border-bottom: 1px solid rgba(255, 255, 255, .18); }
.foot a:hover { color: var(--gold-2); border-color: rgba(212, 175, 55, .5); }

/* On a phone the picture becomes a banner: the welcome and the Open button
   must both be reachable without scrolling. */
@media (max-width: 899px) {
  .hero__art { max-height: 198px; }
  .hero__art img { height: 198px; object-fit: cover; object-position: 62% 42%; }
  h1 { font-size: clamp(40px, 10.5vw, 56px); }
  .lede { font-size: 15.5px; margin-top: 14px; }
  .open { margin-top: 24px; padding: 15px 26px 15px 30px; font-size: 18px; }
}

/* --------------------------------------------------------------- desktop */
@media (min-width: 900px) {
  .page { padding: 40px 40px 48px; }
  .hero { grid-template-columns: 1fr 1.05fr; gap: 56px; }
  .hero__art { order: 2; }
  .hero__text { order: 1; }
  .facts { grid-template-columns: repeat(3, 1fr); gap: 32px; margin-top: 72px; }
  .lede { font-size: 18px; }
}

@media (min-width: 1280px) {
  .hero { grid-template-columns: 1fr 1.15fr; gap: 72px; }
}

/* ---------------------------------------------------------------- motion */
@keyframes rise {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition-duration: .01ms !important; }
}