/* --------------------------------------------------------
   Vow-lang — "The Proof"
   Austere, mathematical, precise.
   -------------------------------------------------------- */

:root {
  /* Brand */
  --brand: oklch(0.58 0.19 32);
  --brand-hover: oklch(0.65 0.20 32);
  --brand-dim: oklch(0.42 0.12 32);

  /* Surfaces — warm-tinted toward brand hue */
  --bg-deep: oklch(0.11 0.006 55);
  --bg: oklch(0.14 0.006 55);
  --bg-surface: oklch(0.18 0.008 55);
  --border: oklch(0.23 0.006 55);

  /* Text */
  --text: oklch(0.91 0.008 55);
  --text-secondary: oklch(0.68 0.006 55);
  --text-muted: oklch(0.48 0.006 55);

  /* Code syntax */
  --syn-keyword: oklch(0.68 0.06 55);
  --syn-function: oklch(0.86 0.02 55);
  --syn-contract: var(--brand);

  /* Typography */
  --font-display: "Sora", sans-serif;
  --font-body: "Albert Sans", sans-serif;
  --font-mono: "Azeret Mono", monospace;

  /* Spacing scale (4pt) */
  --sp-1: 0.25rem;   /* 4 */
  --sp-2: 0.5rem;    /* 8 */
  --sp-3: 0.75rem;   /* 12 */
  --sp-4: 1rem;      /* 16 */
  --sp-6: 1.5rem;    /* 24 */
  --sp-8: 2rem;      /* 32 */
  --sp-12: 3rem;     /* 48 */
  --sp-16: 4rem;     /* 64 */
  --sp-24: 6rem;     /* 96 */
  --sp-32: 8rem;     /* 128 */
}


/* --------------------------------------------------------
   Reset & base
   -------------------------------------------------------- */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.7;
}

.container {
  max-width: 52rem;
  margin: 0 auto;
  padding: 0 var(--sp-6);
}


/* --------------------------------------------------------
   Page-load animation
   -------------------------------------------------------- */

@keyframes reveal {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  @keyframes reveal {
    from { opacity: 1; transform: none; }
    to   { opacity: 1; transform: none; }
  }
}


/* --------------------------------------------------------
   Header
   -------------------------------------------------------- */

header {
  padding: var(--sp-32) 0 var(--sp-24);
  text-align: center;
}

.v-icon {
  width: 88px;
  height: auto;
  opacity: 0;
  animation: reveal 0.7s cubic-bezier(0.16, 1, 0.3, 1) 0.1s both;
}

.wordmark {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 6vw, 4.2rem);
  font-weight: 700;
  margin-top: var(--sp-4);
  letter-spacing: -0.03em;
  line-height: 1.1;
  opacity: 0;
  animation: reveal 0.7s cubic-bezier(0.16, 1, 0.3, 1) 0.2s both;
}

.wm-vow {
  color: var(--brand);
}

.wm-lang {
  color: var(--text);
  font-weight: 300;
}

.tagline {
  font-family: var(--font-body);
  font-size: clamp(1rem, 2vw, 1.15rem);
  color: var(--text-secondary);
  margin-top: var(--sp-6);
  line-height: 1.8;
  max-width: 38ch;
  margin-left: auto;
  margin-right: auto;
  font-weight: 300;
  opacity: 0;
  animation: reveal 0.7s cubic-bezier(0.16, 1, 0.3, 1) 0.35s both;
}


/* --------------------------------------------------------
   Section annotations — code-comment motif
   -------------------------------------------------------- */

.section-annotation {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  margin-bottom: var(--sp-12);
}


/* --------------------------------------------------------
   Properties (features as numbered axioms)
   -------------------------------------------------------- */

.properties {
  padding: var(--sp-24) 0;
}

.property-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-12) var(--sp-16);
}

.property {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--sp-4);
  align-items: start;
}

.property-index {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--brand);
  padding-top: 0.2em;
  line-height: 1;
}

.property h3 {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.3;
  margin-bottom: var(--sp-2);
}

.property p {
  grid-column: 2;
  color: var(--text-secondary);
  font-size: 0.925rem;
  line-height: 1.7;
}

.property code {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--brand);
  background: none;
  padding: 0;
}


/* --------------------------------------------------------
   Proof (code example)
   -------------------------------------------------------- */

.proof {
  padding: var(--sp-24) 0;
  background: var(--bg-deep);
}

.proof h2 {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3vw, 1.8rem);
  font-weight: 600;
  color: var(--text);
  margin-bottom: var(--sp-8);
  letter-spacing: -0.02em;
}

.proof pre {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: var(--sp-8);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  line-height: 1.8;
  tab-size: 2;
}

.proof code {
  font-family: inherit;
  color: var(--text);
}

.proof .kw { color: var(--syn-keyword); }
.proof .fn { color: var(--syn-function); }
.proof .ct { color: var(--syn-contract); }

.proof-caption {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-top: var(--sp-6);
  line-height: 1.7;
  max-width: 65ch;
}

.proof-caption code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--brand);
}


/* --------------------------------------------------------
   Begin (CTA)
   -------------------------------------------------------- */

.begin {
  padding: var(--sp-24) 0;
  text-align: center;
}

.begin h2 {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3vw, 1.8rem);
  font-weight: 600;
  color: var(--text);
  margin-bottom: var(--sp-3);
  letter-spacing: -0.02em;
}

.begin p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: var(--sp-8);
  font-weight: 300;
}

.btn {
  display: inline-block;
  padding: var(--sp-3) var(--sp-8);
  border: 1px solid var(--brand);
  color: var(--brand);
  background: transparent;
  text-decoration: none;
  border-radius: 2px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.01em;
  transition: background 0.25s cubic-bezier(0.16, 1, 0.3, 1),
              color 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.btn:hover {
  background: var(--brand);
  color: var(--bg-deep);
}


/* --------------------------------------------------------
   Footer
   -------------------------------------------------------- */

footer {
  padding: var(--sp-8) 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
}

footer a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

footer a:hover {
  color: var(--text);
}


/* --------------------------------------------------------
   Responsive — mobile
   -------------------------------------------------------- */

@media (max-width: 640px) {
  header {
    padding: var(--sp-16) 0 var(--sp-12);
  }

  .v-icon {
    width: 64px;
  }

  .wordmark {
    margin-top: var(--sp-3);
  }

  .tagline {
    margin-top: var(--sp-4);
  }

  .section-annotation {
    margin-bottom: var(--sp-8);
  }

  .properties {
    padding: var(--sp-16) 0;
  }

  .property-list {
    grid-template-columns: 1fr;
    gap: var(--sp-8);
  }

  .proof {
    padding: var(--sp-16) 0;
  }

  .proof pre {
    padding: var(--sp-4);
    font-size: 0.78rem;
    line-height: 1.7;
  }

  .begin {
    padding: var(--sp-16) 0;
  }
}