/* ═══════════════════════════════════════════════════════════════════
   AlgoStream — shared design system
   Used by:  /index.html  ·  /dev/bench/index.html  ·  /guides/*.html
   Dark-only by design. No webfonts, no external requests.
   ═══════════════════════════════════════════════════════════════════ */

/* ───── design tokens ─────────────────────────────────────────── */
:root {
  --bg:           #0A0A0B;
  --surface:      #111114;
  --border:       #1B1B22;
  --border-hi:    #2A2A33;
  --amber:        #FFA21A;
  --amber-dim:    #B8761A;
  --amber-deep:   #6B4810;
  --cream:        #E8E4DA;
  --muted:        #76726A;
  --dim:          #43403A;
  --live:         #4AE25A;
  --warn:         #E2724A;

  --mono:
    ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code",
    Menlo, Monaco, Consolas, "Liberation Mono", monospace;

  --grid: rgba(255, 162, 26, 0.035);
  --tnum: 'tnum' 1, 'zero' 1;
}

*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { background: var(--bg); }

body {
  min-height: 100vh;
  background: var(--bg);
  color: var(--cream);
  font-family: var(--mono);
  font-size: 14px;
  line-height: 1.5;
  font-feature-settings: var(--tnum);
  letter-spacing: -0.005em;
  overflow-x: hidden;
  position: relative;
}

::selection { background: var(--amber); color: var(--bg); }

/* ───── ambient layers ───────────────────────────────────────── */
.canvas {
  position: fixed; inset: 0; pointer-events: none; z-index: 0;
  background-image:
    radial-gradient(60% 50% at 82% 18%, rgba(255,162,26,0.07), transparent 70%),
    radial-gradient(50% 50% at 8% 88%, rgba(255,162,26,0.025), transparent 65%),
    repeating-linear-gradient(0deg, transparent 0 39px, var(--grid) 39px 40px),
    repeating-linear-gradient(90deg, transparent 0 39px, var(--grid) 39px 40px);
}
.grain {
  position: fixed; inset: 0; pointer-events: none; z-index: 1;
  opacity: 0.35; mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='200' height='200' filter='url(%23n)' opacity='0.5'/%3E%3C/svg%3E");
}
.vignette {
  position: fixed; inset: 0; pointer-events: none; z-index: 1;
  background: radial-gradient(120% 90% at 50% 50%, transparent 55%, rgba(0,0,0,0.55) 100%);
}

/* ───── shell ─────────────────────────────────────────────────── */
.shell {
  position: relative; z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px 40px 32px;
  display: grid;
  grid-template-rows: auto 1fr auto;
  gap: 36px;
  min-height: 100vh;
}

/* ───── status bar ────────────────────────────────────────────── */
.statusbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
  animation: fade 0.55s ease-out both;
}
.statusbar .group { display: flex; gap: 14px; align-items: center; flex-wrap: wrap; }
.statusbar .sep { color: var(--dim); }
.statusbar .mark {
  color: var(--cream);
  font-weight: 600;
  letter-spacing: 0.18em;
}
.statusbar .live {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--cream);
}
.live-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--live);
  box-shadow: 0 0 8px var(--live);
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%      { opacity: 0.45; transform: scale(0.9); }
}

/* ───── links ─────────────────────────────────────────────────── */
.link {
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid rgba(255,162,26,0.28);
  transition: border-color .18s ease, color .18s ease;
}
.link:hover { border-bottom-color: var(--amber); }

.backlink {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--muted);
  text-decoration: none;
  transition: color .18s ease;
}
.backlink:hover { color: var(--amber); }
.backlink .glyph { transition: transform .22s cubic-bezier(.2,.8,.2,1); }
.backlink:hover .glyph { transform: translateX(-4px); }

/* ───── panel ────────────────────────────────────────────────── */
.panel {
  position: relative;
  background:
    linear-gradient(180deg, rgba(255,162,26,0.025), transparent 40%),
    var(--surface);
  border: 1px solid var(--border-hi);
  box-shadow:
    0 0 0 1px var(--bg),
    0 30px 60px -30px rgba(0,0,0,0.7),
    inset 0 1px 0 rgba(255,255,255,0.02);
}
.panel::before, .panel::after,
.panel .br-tr, .panel .br-bl {
  content: ""; position: absolute; width: 14px; height: 14px;
  pointer-events: none;
}
.panel::before { top: -1px; left: -1px;
  border-top: 1px solid var(--amber); border-left: 1px solid var(--amber); }
.panel::after  { bottom: -1px; right: -1px;
  border-bottom: 1px solid var(--amber); border-right: 1px solid var(--amber); }
.panel .br-tr { top: -1px; right: -1px;
  border-top: 1px solid var(--amber-deep); border-right: 1px solid var(--amber-deep); }
.panel .br-bl { bottom: -1px; left: -1px;
  border-bottom: 1px solid var(--amber-deep); border-left: 1px solid var(--amber-deep); }

.panel-head, .panel-foot {
  display: flex; justify-content: space-between; align-items: center;
  gap: 16px;
  padding: 11px 16px;
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}
.panel-head { border-bottom: 1px solid var(--border); }
.panel-foot { border-top:    1px solid var(--border); color: var(--dim); }
.panel-head .seq { color: var(--amber-dim); }

/* ───── metric cells ─────────────────────────────────────────── */
.metrics {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
}
.metric {
  background: var(--surface);
  padding: 22px 18px 20px;
  position: relative;
}
.metric .label {
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 10px;
}
.metric .value {
  font-size: clamp(28px, 3vw, 34px);
  font-weight: 600;
  letter-spacing: -0.035em;
  color: var(--amber);
  line-height: 1;
  font-feature-settings: var(--tnum);
  text-shadow: 0 0 16px rgba(255,162,26,0.18);
  display: inline-flex; align-items: baseline;
}
.metric .value .unit {
  font-size: 13px;
  font-weight: 500;
  color: var(--amber-dim);
  letter-spacing: 0;
  margin-left: 4px;
  text-shadow: none;
}
.metric .note {
  margin-top: 12px;
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.005em;
  max-width: 28ch;
}

/* ───── CTAs ─────────────────────────────────────────────────── */
.ctas {
  display: flex; gap: 12px; flex-wrap: wrap;
  animation: rise 0.7s cubic-bezier(.2,.8,.2,1) 0.5s both;
}
.btn {
  display: inline-flex; align-items: center; gap: 14px;
  padding: 14px 22px;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 600;
  text-decoration: none;
  transition:
    transform .15s ease,
    box-shadow .25s ease,
    background-color .2s ease,
    color .2s ease,
    border-color .2s ease;
}
.btn-primary {
  color: var(--bg);
  background: var(--amber);
  border: 1px solid var(--amber);
  box-shadow:
    0 0 0 1px rgba(255,162,26,0.4),
    0 12px 32px -12px rgba(255,162,26,0.55);
}
.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow:
    0 0 0 1px rgba(255,162,26,0.6),
    0 18px 44px -12px rgba(255,162,26,0.7);
}
.btn-ghost {
  color: var(--cream);
  background: transparent;
  border: 1px solid var(--border-hi);
}
.btn-ghost:hover {
  color: var(--amber);
  border-color: var(--amber);
  transform: translateY(-1px);
}
.btn .arrow { transition: transform .25s cubic-bezier(.2,.8,.2,1); }
.btn:hover .arrow { transform: translateX(5px); }

/* ───── footer ───────────────────────────────────────────────── */
.footer {
  display: grid;
  grid-template-columns: minmax(0, auto) 1fr minmax(0, auto);
  gap: 32px;
  align-items: center;
  padding-top: 22px;
  border-top: 1px solid var(--border);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  animation: fade 0.6s ease-out 0.7s both;
}
.ascii-mark {
  font-size: 10.5px;
  line-height: 1.45;
  color: var(--amber-dim);
  white-space: pre;
  letter-spacing: 0;
  text-transform: none;
  /* No margin reset — <pre>'s default 1em keeps the footer rhythm the
     landing page shipped with. */
}
.ascii-mark .dim   { color: var(--dim); }
.ascii-mark .check { color: var(--live); }
.ascii-mark a {
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid rgba(255,162,26,0.28);
}
.ascii-mark a:hover { border-bottom-color: var(--amber); }

.spark {
  width: 100%; height: 40px;
  opacity: 0.85;
}
.spark .line { stroke: var(--amber); stroke-width: 1.2; fill: none; stroke-linecap: round; stroke-linejoin: round; }
.spark .fill { fill: url(#spark-grad); }
.spark .axis { stroke: var(--dim); stroke-width: 1; stroke-dasharray: 2 4; }
.spark .tick { fill: var(--muted); font-size: 8px; font-family: var(--mono); letter-spacing: 0.1em; }

.meta-right {
  text-align: right;
  color: var(--muted);
}
.meta-right strong {
  color: var(--cream); font-weight: 600;
}
.meta-right a { color: inherit; text-decoration: none; }
.meta-right a:hover { color: var(--amber); }

/* ───── animations ────────────────────────────────────────────── */
@keyframes fade { from { opacity: 0; } to { opacity: 1; } }
@keyframes rise {
  from { opacity: 0; transform: translateY(14px); filter: blur(4px); }
  to   { opacity: 1; transform: translateY(0);    filter: blur(0); }
}
.stagger > * { animation: rise 0.55s cubic-bezier(.2,.8,.2,1) both; }
.stagger > *:nth-child(1) { animation-delay: 0.50s; }
.stagger > *:nth-child(2) { animation-delay: 0.60s; }
.stagger > *:nth-child(3) { animation-delay: 0.70s; }
.stagger > *:nth-child(4) { animation-delay: 0.80s; }

/* ───── responsive ────────────────────────────────────────────── */
@media (max-width: 720px) {
  .shell { padding: 20px 22px 24px; gap: 24px; }
  .statusbar { flex-direction: column; align-items: flex-start; gap: 8px; }
  .footer { grid-template-columns: 1fr; gap: 18px; text-align: left; }
  .meta-right { text-align: left; }
  .ctas { flex-direction: column; align-items: stretch; }
  .btn { justify-content: space-between; }
}

/* reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  .live-dot { animation: none; opacity: 1; }
}