@layer reset, tokens, base, layout, components;

@layer tokens {
  @font-face {
    font-family: "Offside";
    src: url("/assets/fonts/Offside-Regular.woff2") format("woff2");
    font-weight: 400;
    font-style: normal;
    font-display: swap;
  }

  @font-face {
    font-family: "Outfit";
    /* Plain woff2, not woff2-variations: the legacy format string is rejected outright
       by some engines, and a variable font loads fine declared this way */
    src: url("/assets/fonts/Outfit-Variable.woff2") format("woff2");
    font-weight: 100 900;
    font-style: normal;
    font-display: swap;
  }

  :root {
    color-scheme: dark;

    /* True black is the product doctrine, not a style choice: OLED pixels at #000 are off */
    --bg: oklch(0 0 0);
    --ink: oklch(0.95 0.004 250);
    --muted: oklch(0.7 0.012 250);
    /* Floor is set by the 14px footer text needing 4.5:1 on true black, not by taste */
    --faint: oklch(0.63 0.014 250);

    /* OIII at 500.7nm is the emission line that makes real nebulae read teal */
    --oiii: oklch(0.82 0.13 178);
    --edge: oklch(1 0 0 / 0.13);
    --edge-strong: oklch(1 0 0 / 0.28);

    --font-display: "Offside", ui-sans-serif, system-ui, sans-serif;
    --font-body: "Outfit", ui-sans-serif, system-ui, sans-serif;

    --step-0: clamp(1rem, 0.96rem + 0.2vw, 1.125rem);
    --step-1: clamp(1.35rem, 1.24rem + 0.55vw, 1.75rem);
    --step-2: clamp(1.5rem, 1.34rem + 0.8vw, 2rem);
    --wordmark: clamp(2.75rem, 1.4rem + 6.2vw, 5.75rem);

    --gutter: clamp(1.25rem, 5vw, 4rem);
    --shell: 68rem;

    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);

    --z-sky: 0;
    --z-content: 1;
    --z-skip: 10;
  }
}

@layer reset {
  *, *::before, *::after { box-sizing: border-box; }

  body, h1, h2, p, figure { margin: 0; }

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

  :where(a) { color: inherit; }

  :where(img, svg, canvas) { display: block; max-inline-size: 100%; }

  :focus-visible {
    outline: 2px solid var(--oiii);
    outline-offset: 3px;
    border-radius: 2px;
  }

  @media (prefers-reduced-motion: no-preference) {
    html { scroll-behavior: smooth; }
  }
}

@layer base {
  body {
    background: var(--bg);
    color: var(--ink);
    font-family: var(--font-body);
    font-size: var(--step-0);
    /* Light type on black reads thinner than it measures; 350 holds up where 300 fades */
    font-weight: 350;
    line-height: 1.7;
    /* Offside ships one weight; synthesis would smear it into fake bolds */
    font-synthesis: none;
    -webkit-font-smoothing: antialiased;
  }

  h1, h2 {
    font-family: var(--font-display);
    font-weight: 400;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    line-height: 1.1;
    text-wrap: balance;
  }

  p { text-wrap: pretty; }

  .skip-link {
    position: absolute;
    inset-block-start: 0;
    inset-inline-start: 50%;
    translate: -50% -110%;
    z-index: var(--z-skip);
    padding: 0.7em 1.4em;
    background: var(--ink);
    color: var(--bg);
    text-decoration: none;
    transition: translate 0.2s var(--ease-out);
  }
  .skip-link:focus-visible { translate: -50% 0; }
}

@layer layout {
  .hero {
    position: relative;
    display: grid;
    place-items: center;
    min-block-size: 100svb;
    padding: calc(var(--gutter) * 1.5) var(--gutter);
    overflow: clip;
  }

  .hero__sky {
    position: absolute;
    inset: 0;
    z-index: var(--z-sky);
    inline-size: 100%;
    block-size: 100%;
  }

  /* Sits under the canvas so the deep field has depth before a single star draws */
  .hero::before {
    content: "";
    position: absolute;
    inset: 0;
    z-index: var(--z-sky);
    background:
      radial-gradient(60% 45% at 22% 18%, oklch(0.35 0.08 205 / 0.3), transparent 70%),
      radial-gradient(55% 50% at 82% 72%, oklch(0.32 0.1 320 / 0.22), transparent 72%),
      radial-gradient(90% 70% at 50% 55%, oklch(0.16 0.03 260 / 0.55), transparent 78%);
  }

  /* Keeps the copy legible over whatever the sky is doing behind it */
  .hero__body::before {
    content: "";
    position: absolute;
    inset: -8% -12%;
    z-index: -1;
    background: radial-gradient(closest-side, oklch(0 0 0 / 0.72), transparent);
    pointer-events: none;
  }

  .hero__body {
    position: relative;
    z-index: var(--z-content);
    max-inline-size: 46ch;
    text-align: center;
  }

  .about {
    padding: clamp(4rem, 12vw, 9rem) var(--gutter);
    border-block-start: 1px solid var(--edge);
  }

  .about__grid {
    max-inline-size: var(--shell);
    margin-inline: auto;
    display: grid;
    gap: clamp(2.5rem, 5vw, 4rem);
    grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr));
  }

  .foot {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 0.5rem 2rem;
    max-inline-size: var(--shell);
    margin-inline: auto;
    padding: 2rem var(--gutter) 3rem;
    color: var(--faint);
    font-size: 0.875rem;
  }
}

@layer components {
  .wordmark {
    font-size: var(--wordmark);
    letter-spacing: 0.1em;
    /* Tracking adds a trailing gap after the last letter; pull it back so the word centres optically */
    margin-inline-end: -0.1em;
  }

  .hero__line {
    margin-block-start: 1.5rem;
    color: var(--muted);
    font-size: var(--step-1);
    line-height: 1.55;
  }

  .actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.75rem;
    margin-block-start: 2.5rem;
  }

  .btn {
    display: inline-flex;
    align-items: center;
    gap: 0.55em;
    padding: 0.75em 1.5em;
    border: 1px solid var(--edge-strong);
    border-radius: 6px;
    background: oklch(0 0 0 / 0.4);
    color: var(--ink);
    font-size: 0.95rem;
    text-decoration: none;
    transition:
      border-color 0.25s var(--ease-out),
      color 0.25s var(--ease-out),
      background-color 0.25s var(--ease-out);
  }

  .btn:hover { border-color: var(--oiii); color: var(--oiii); }

  .btn--primary {
    border-color: var(--oiii);
    color: var(--oiii);
  }
  .btn--primary:hover { background: oklch(0.82 0.13 178 / 0.14); }

  /* Sized in em so the mark tracks the label instead of pinning itself to a pixel */
  .btn__mark {
    flex: none;
    inline-size: 1.05em;
    block-size: auto;
  }

  .hero__scroll {
    position: absolute;
    inset-block-end: clamp(1.25rem, 3vh, 2.5rem);
    inset-inline: 0;
    z-index: var(--z-content);
    margin-inline: auto;
    inline-size: max-content;
    padding: 0.5rem;
    color: var(--faint);
    transition: color 0.25s var(--ease-out);
  }
  .hero__scroll:hover { color: var(--oiii); }

  .hero__scroll svg {
    inline-size: 0.75rem;
    block-size: auto;
  }

  .note__title {
    font-size: var(--step-2);
    color: var(--ink);
  }

  .note p {
    margin-block-start: 0.9rem;
    max-inline-size: 42ch;
    color: var(--muted);
  }

  .foot a {
    color: var(--muted);
    text-decoration-color: var(--edge-strong);
    text-underline-offset: 0.25em;
  }
  .foot a:hover { color: var(--oiii); }
}

@layer components {
  @media (prefers-reduced-motion: no-preference) {
    .hero__body > * {
      animation: rise 0.9s var(--ease-out) both;
      animation-delay: calc(var(--i, 0) * 110ms);
    }
    .hero__line { --i: 1; }
    .actions { --i: 2; }

    .hero__scroll svg {
      animation: nudge 3.2s var(--ease-out) infinite;
    }

    @supports (animation-timeline: view()) {
      .note {
        animation: settle 0.8s var(--ease-out) both;
        animation-timeline: view();
        animation-range: entry 5% cover 22%;
      }
    }
  }

  @keyframes rise {
    from { opacity: 0; translate: 0 0.85rem; }
  }

  /* Movement only, never opacity: a scroll timeline that never advances
     (headless render, hidden tab, print) must still leave the text readable */
  @keyframes settle {
    from { translate: 0 1.25rem; }
  }

  @keyframes nudge {
    0%, 62%, 100% { translate: 0 0; }
    76% { translate: 0 0.3rem; }
  }
}