/* Shared by every page: the colour tokens and the floating bar. home.css builds the homepage on top of this. */

:root {
  color-scheme: light;

  --bg: #ffffff;
  --ink: #1d252c;
  --muted: #56636e;
  --faint: #a6b1bc;
  --rule: rgba(79,93,106,0.18);
  --card: rgba(255,255,255,0.86);
  --grid: rgba(79,93,106,0.08);
  --glass: rgba(255,255,255,0.6);

  --tb-top: #f7f9fa;
  --tb-paper: #f2f4f5;
  --tb-s3: #dde3e8;
  --tb-s2: #c6cfd7;
  --tb-s1: #a6b1bc;
  --tb-s0: #8592a0;
  --tb-hi: #4f5d6a;
  --tb-lit: #f5b301;
  --tb-ink: #3c4852;
  --tb-seaTop: #a9c8e1;
  --tb-seaL: #7fa7c9;
  --tb-seaR: #5f8db5;
  --tb-seaEdge: #4f6f8c;
  --tb-wave: #ffffff;
  --tb-beacon: #e0402e;
  --tb-bg: #ffffff;
  --tb-beacon-op: 0.85;

  --accent: #d8b750;
  --on-accent: #1d252c;
  --mono: 'Space Mono', monospace;
  --gutter: clamp(20px, 3vw, 40px);
}

[data-theme=dark] {
  color-scheme: dark;

  --bg: #000000;
  --ink: #eef2f5;
  --muted: #a9b4be;
  --faint: #5c6873;
  --rule: rgba(201,210,218,0.16);
  --card: rgba(8,10,12,0.82);
  --grid: rgba(201,210,218,0.07);
  --glass: rgba(0,0,0,0.58);

  --tb-top: #3b444d;
  --tb-paper: #323a42;
  --tb-s3: #2a3138;
  --tb-s2: #222930;
  --tb-s1: #1b2127;
  --tb-s0: #14191d;
  --tb-hi: #9aa7b3;
  --tb-lit: #f5b301;
  --tb-ink: #c9d2da;
  --tb-seaTop: #0e2236;
  --tb-seaL: #0a1a2a;
  --tb-seaR: #07131f;
  --tb-seaEdge: #3d5a75;
  --tb-wave: #4f7396;
  --tb-beacon: #ff4d3d;
  --tb-bg: #000000;
  --tb-beacon-op: 1;
}

/* A floating bar: held the same distance off the top and both sides so the animation runs on round it. */
.nav {
  --nav-float: 12px;
  position: sticky;
  top: var(--nav-float);
  z-index: 5;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  margin: var(--nav-float) var(--nav-float) 0;
  padding: 6px 22px;
  border: 1px solid var(--rule);
  border-radius: 12px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  isolation: isolate;
}

/* The bar's frosted glass, on its own layer so the words can be cut out of it: nav.js draws the name, and on a wide screen the links, into --etch-mask, a canvas the size of this layer, in the page's own font and at their places. */
.nav::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  border-radius: inherit;
  background: var(--glass);
  -webkit-backdrop-filter: blur(10px) saturate(1.1);
  backdrop-filter: blur(10px) saturate(1.1);
}

.nav.is-etched::before {
  -webkit-mask: linear-gradient(#000 0 0), var(--etch-mask) no-repeat 0 0 / 100% 100%;
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0), var(--etch-mask) no-repeat 0 0 / 100% 100%;
  mask-composite: exclude;
}

/* The cut's lower inside edge catches the light: the letters less the same letters raised half a pixel leave a hairline along each one's foot. */
.nav.is-etched::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  border-radius: inherit;
  pointer-events: none;
  background: rgba(255, 255, 255, 0.6);
  -webkit-mask: var(--etch-mask) no-repeat 0 0 / 100% 100%, var(--etch-mask) no-repeat 0 -0.5px / 100% 100%;
  -webkit-mask-composite: source-out;
  mask: var(--etch-mask) no-repeat 0 0 / 100% 100%, var(--etch-mask) no-repeat 0 -0.5px / 100% 100%;
  mask-composite: subtract;
}

/* Cut through, the words show the sea itself. They stay in the page as text for reading, selecting and clicking. */
.nav.is-etched .nav-brand { color: transparent; }
.nav.is-etched-links .nav-link { color: transparent; }

/* Under the pointer a cut word frosts over, a pale wash on the sea, since fading transparent text would show nothing. */
.nav.is-etched .nav-brand:hover,
.nav.is-etched-links .nav-link:hover { color: rgba(255, 255, 255, 0.55); opacity: 1; }

/* The dark glass barely differs from the dark sea, so cut words are lost against it; at night they are plain light text again. */
[data-theme="dark"] .nav.is-etched::before { -webkit-mask: none; mask: none; }
[data-theme="dark"] .nav.is-etched::after { display: none; }
[data-theme="dark"] .nav.is-etched .nav-brand { color: var(--ink); }
[data-theme="dark"] .nav.is-etched-links .nav-link { color: var(--muted); }
[data-theme="dark"] .nav.is-etched .nav-brand:hover { opacity: 0.72; }
[data-theme="dark"] .nav.is-etched-links .nav-link:hover { opacity: 0.72; }

.nav-brand {
  text-decoration: none;
  font-weight: 700;
  font-size: 13px;
  color: var(--ink);
  padding: 14px 0;
  transition: color 0.2s;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: wrap;
  margin-left: auto;
}

.nav-tools {
  display: flex;
  align-items: center;
}

.nav-link {
  text-decoration: none;
  color: var(--muted);
  padding: 14px 8px;
  transition: color 0.2s;
}

.theme-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  /* The extra width is the touch target; this keeps the icon in line with the bar's inner edge. */
  margin: 0 -13px 0 6px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
}

.theme-btn:hover { color: var(--ink); }

.theme-icon {
  display: block;
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* The menu button stands in for the links on a phone. */
.menu-btn {
  display: none;
  align-items: center;
  justify-content: center;
  margin-right: -13px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
}

.menu-icon {
  display: block;
  width: 20px;
  height: 20px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
}

.menu-icon--close,
.nav[data-open] .menu-icon--open { display: none; }
.nav[data-open] .menu-icon--close { display: block; }

.theme-icon--sun { display: none; }
[data-theme="dark"] .theme-icon--sun { display: block; }
[data-theme="dark"] .theme-icon--moon { display: none; }

/* The bar's own hover dim, so pages without home.css get it too. */
.nav-brand:hover,
.nav-link:hover { opacity: 0.72; }

@media (max-width: 899px) {
  /* The links fold into a menu: a second floating card under the bar, over the page rather than pushing it down. */
  .nav { flex-wrap: nowrap; }
  .menu-btn { display: inline-flex; }
  .theme-btn { margin-right: 0; }
  .nav-links {
    display: none;
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin: 0;
    padding: 6px 22px;
    background: var(--card);
    border: 1px solid var(--rule);
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  }
  .nav[data-open] .nav-links { display: flex; }
  .nav-link { padding: 14px 0; }
  .nav-link + .nav-link { border-top: 1px solid var(--rule); }
}