/* ============================================================================
   Glass Carter — styles.css
   Editorial / technology aesthetic. System fonts only. One accent colour.
   Structure: tokens · reset · primitives · header · hero · sections · cards
   · footer · responsive · motion
   ========================================================================== */

/* --- Design tokens --------------------------------------------------------- */
:root {
  --paper:        #f7f6f3;
  --paper-alt:    #efede8;
  --ink:          #16171a;
  --ink-soft:     #34363b;
  --muted:        #6b6e76;
  --hairline:     #e2e0d9;
  --accent:       #1b4dff;
  --accent-ink:   #ffffff;

  --maxw:         1140px;
  --gutter:       clamp(1.25rem, 5vw, 3.5rem);
  --section-y:    clamp(4rem, 8vw, 6.5rem);

  --font: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
          Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji", sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
          "Liberation Mono", monospace;

  --step--1: clamp(0.82rem, 0.78rem + 0.2vw, 0.9rem);
  --step-0:  clamp(1rem, 0.96rem + 0.2vw, 1.08rem);
  --step-1:  clamp(1.2rem, 1.1rem + 0.5vw, 1.4rem);
  --step-2:  clamp(1.6rem, 1.35rem + 1.2vw, 2.2rem);
  --step-3:  clamp(2.2rem, 1.7rem + 2.5vw, 3.4rem);
  --step-4:  clamp(2.9rem, 2rem + 4.4vw, 4.9rem);

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper:      #121316;
    --paper-alt:  #17181c;
    --ink:        #f3f2ee;
    --ink-soft:   #d7d6d1;
    --muted:      #9a9ca3;
    --hairline:   #2b2d32;
    --accent:     #7f9cff;
    --accent-ink: #0d0f13;
  }
}

/* --- Reset --------------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: var(--step-0);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; }

h1, h2, h3 {
  line-height: 1.08;
  letter-spacing: -0.02em;
  font-weight: 600;
  text-wrap: balance;
}

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

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--ink);
  color: var(--paper);
  padding: 0.6rem 1rem;
  z-index: 100;
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; }

/* --- Layout primitives -------------------------------------------------- */
.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.eyebrow {
  font-family: var(--mono);
  font-size: var(--step--1);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.prose p + p { margin-top: 1.1em; }
.prose p { color: var(--ink-soft); max-width: 60ch; }

/* --- Buttons ---------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.9rem 1.5rem;
  font-size: var(--step--1);
  font-weight: 550;
  letter-spacing: 0.02em;
  text-decoration: none;
  border: 1px solid var(--ink);
  transition: background-color 0.25s var(--ease), color 0.25s var(--ease),
              transform 0.25s var(--ease);
}
.btn--primary { background: var(--ink); color: var(--paper); }
.btn--primary:hover { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn--ghost { background: transparent; color: var(--ink); }
.btn--ghost:hover { background: var(--ink); color: var(--paper); }
@media (prefers-reduced-motion: no-preference) {
  .btn:active { transform: translateY(1px); }
}

/* --- Header ------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--hairline);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
}
.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.wordmark__mark { color: var(--accent); display: inline-flex; }
.wordmark__text { font-size: 1.05rem; }

.site-nav { display: flex; align-items: center; }
.nav-list {
  list-style: none;
  padding: 0;
  display: flex;
  gap: clamp(1rem, 3vw, 2.25rem);
}
.nav-list a {
  text-decoration: none;
  font-size: var(--step--1);
  letter-spacing: 0.02em;
  color: var(--ink-soft);
  padding-block: 0.4rem;
  position: relative;
}
.nav-list a::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.28s var(--ease);
}
.nav-list a:hover { color: var(--ink); }
.nav-list a:hover::after { transform: scaleX(1); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.5rem;
  background: none;
  border: 1px solid var(--hairline);
  padding: 0.5rem 0.8rem;
  font: inherit;
  font-size: var(--step--1);
  color: var(--ink);
  cursor: pointer;
}
.nav-toggle__bars,
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  display: block;
  width: 18px;
  height: 1.5px;
  background: currentColor;
  transition: transform 0.25s var(--ease), opacity 0.2s var(--ease);
}
.nav-toggle__bars { position: relative; }
.nav-toggle__bars::before { position: absolute; top: -6px; }
.nav-toggle__bars::after  { position: absolute; top: 6px; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after  { transform: translateY(-6px) rotate(-45deg); }

/* --- Hero -------------------------------------------------------------- */
.hero { padding-block: clamp(3.5rem, 9vw, 7rem) clamp(3rem, 8vw, 6rem); }
.hero__grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: clamp(2rem, 6vw, 5rem);
  align-items: center;
}
.hero__copy .eyebrow { margin-bottom: 1.5rem; }
.hero h1 { font-size: var(--step-4); margin-bottom: 1.5rem; }
.hero__lede {
  font-size: var(--step-1);
  color: var(--ink-soft);
  max-width: 46ch;
  margin-bottom: 2.25rem;
}
.hero__actions { display: flex; flex-wrap: wrap; gap: 0.9rem; }

.hero__visual { color: var(--ink); }
.figure { width: 100%; height: auto; overflow: visible; }
.figure__pane { fill: none; stroke: var(--ink); stroke-width: 1.4; opacity: 0.9; }
.figure__pane--1 { stroke: var(--muted); }
.figure__pane--3 { stroke: var(--accent); }
.figure__path { stroke: var(--accent); }
.figure__node { fill: var(--ink); }
.figure__node--end { fill: var(--accent); }

/* --- Sections -------------------------------------------------------------- */
.section { padding-block: var(--section-y); border-top: 1px solid var(--hairline); }
.section--alt { background: var(--paper-alt); }

/* Keep section headings clear of the sticky header when jumped to via nav. */
:target { scroll-margin-top: 90px; }
.section, .hero { scroll-margin-top: 76px; }

.section__grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: clamp(1.75rem, 6vw, 5rem);
}
.section__head h2 { font-size: var(--step-3); margin-top: 0.9rem; }
.section__head--wide { max-width: 40ch; margin-bottom: clamp(2.5rem, 6vw, 4rem); }
.section__head--wide h2 { font-size: var(--step-3); margin-top: 0.9rem; }
.section__intro { margin-top: 1.1rem; color: var(--muted); max-width: 48ch; }
.section__body .eyebrow { display: block; }

.callout {
  margin-top: 2rem;
  padding: 1.5rem 1.75rem;
  border: 1px solid var(--hairline);
  border-left: 2px solid var(--accent);
  background: color-mix(in srgb, var(--paper) 60%, transparent);
}
.callout .eyebrow { margin-bottom: 0.75rem; }
.callout p:last-child { color: var(--ink-soft); }

/* --- Cards ------------------------------------------------------------- */
.cards {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--hairline);
}
.card {
  padding: 2rem 1.5rem 2.25rem 0;
  border-right: 1px solid var(--hairline);
  padding-right: 1.5rem;
  transition: background-color 0.3s var(--ease);
}
.card:last-child { border-right: 0; }
.card__index { font-family: var(--mono); font-size: var(--step--1); color: var(--accent); }
.card__title { font-size: var(--step-1); margin: 1.25rem 0 0.75rem; }
.card__text { color: var(--ink-soft); font-size: 0.98rem; }
.card:hover { background: color-mix(in srgb, var(--accent) 6%, transparent); }

/* --- Footer ---------------------------------------------------------------- */
.site-footer {
  border-top: 1px solid var(--hairline);
  padding-block: clamp(2.5rem, 6vw, 4rem);
}
.footer-inner { display: grid; gap: 0.4rem; }
.footer__brand { font-weight: 600; letter-spacing: -0.01em; }
.footer__tag { font-family: var(--mono); font-size: var(--step--1); letter-spacing: 0.08em; color: var(--muted); }
.footer__legal { font-size: var(--step--1); color: var(--muted); margin-top: 0.75rem; }

.contact__email { margin-top: 1.5rem; }
.contact__email a {
  font-size: clamp(1.15rem, 0.9rem + 1.6vw, 1.9rem);
  letter-spacing: -0.02em;
  text-decoration: none;
  border-bottom: 2px solid var(--accent);
  padding-bottom: 2px;
  overflow-wrap: anywhere;
}
.contact__email a:hover { color: var(--accent); }

/* --- Responsive ---------------------------------------------------------- */
@media (max-width: 900px) {
  .hero__grid { grid-template-columns: 1fr; }
  .hero__visual { order: -1; max-width: 340px; }
  .section__grid { grid-template-columns: 1fr; }
  .cards { grid-template-columns: repeat(2, 1fr); }
  .card { border-right: 0; border-bottom: 1px solid var(--hairline); padding: 1.75rem 0; }
  .card:nth-child(odd) { border-right: 1px solid var(--hairline); padding-right: 1.5rem; }
}

@media (max-width: 620px) {
  .nav-toggle { display: inline-flex; }
  .site-nav { position: relative; }
  .nav-list {
    position: absolute;
    right: 0;
    top: calc(100% + 14px);
    flex-direction: column;
    gap: 0;
    min-width: 200px;
    background: var(--paper);
    border: 1px solid var(--hairline);
    padding: 0.5rem;
    box-shadow: 0 18px 40px -20px rgba(0,0,0,0.3);
    display: none;
  }
  .nav-list.is-open { display: flex; }
  .nav-list a { display: block; padding: 0.7rem 0.6rem; }
  .nav-list a::after { display: none; }
  .cards { grid-template-columns: 1fr; }
  .card, .card:nth-child(odd) { border-right: 0; padding-right: 0; }
}

/* --- Motion ------------------------------------------------------------- */
@media (prefers-reduced-motion: no-preference) {
  /* Content is always visible by default. When JS + IntersectionObserver are
     available, elements scrolling into view REPLAY this entrance animation from
     a hidden state. If JS never runs, nothing is ever hidden. */
  .js .reveal.is-visible {
    animation: reveal-in 0.7s var(--ease) both;
  }
  @keyframes reveal-in {
    from { opacity: 0; transform: translateY(18px); }
    to   { opacity: 1; transform: none; }
  }

  /* Staggered entrance for the hero figure. `both` holds the `from` state
     during the delay; if animations are unavailable the elements simply keep
     their normal (visible) styles. */
  .figure__pane, .figure__path, .figure__node {
    animation: figure-in 0.9s var(--ease) both;
  }
  .figure__pane--1 { animation-delay: 0.05s; }
  .figure__pane--2 { animation-delay: 0.18s; }
  .figure__pane--3 { animation-delay: 0.31s; }
  .figure__path    { animation-delay: 0.5s; }
  .figure__node    { animation-delay: 0.7s; }
  @keyframes figure-in { from { opacity: 0; } to { opacity: 1; } }
}