/* Splitmark Stopwatch — precision instrument + laboratory logbook */

:root {
  --bg: #F1F2EF;
  --ink: #25313A;
  --panel: #17212A;
  --display: #F6F4E9;
  --accent: #E3A34B;
  --secondary: #718A89;
  --border: #D3D8D5;
  --paper: #FBFBFA;
  --max: 1220px;
  --font-sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-serif: ui-serif, Georgia, "Times New Roman", serif;
  --font-mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background-color: var(--bg);
  background-image:
    url("../svg/timing-field.svg"),
    repeating-linear-gradient(
      90deg,
      transparent 0,
      transparent 47px,
      rgba(37, 49, 58, 0.035) 47px,
      rgba(37, 49, 58, 0.035) 48px
    ),
    repeating-linear-gradient(
      0deg,
      transparent 0,
      transparent 23px,
      rgba(113, 138, 137, 0.04) 23px,
      rgba(113, 138, 137, 0.04) 24px
    );
  background-size: 240px 160px, 48px 48px, 24px 24px;
  font-family: var(--font-serif);
  font-size: 18px;
  line-height: 1.65;
}

img, svg { max-width: 100%; }

a {
  color: var(--ink);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover { color: #152028; }

h1, h2, h3, h4 {
  font-family: var(--font-sans);
  font-weight: 650;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 0.6em;
}

p { margin: 0 0 1em; }

.skip-link {
  position: absolute;
  left: 12px;
  top: -40px;
  background: var(--panel);
  color: var(--display);
  padding: 8px 12px;
  z-index: 20;
}

.skip-link:focus { top: 8px; }

.wrap {
  width: min(100% - 32px, var(--max));
  margin-inline: auto;
}

.wrap-narrow {
  width: min(100% - 32px, 720px);
  margin-inline: auto;
}

/* Masthead */

.masthead {
  height: 62px;
  border-bottom: 1px solid var(--border);
  background: rgba(241, 242, 239, 0.94);
  position: sticky;
  top: 0;
  z-index: 10;
}

.masthead-inner {
  height: 62px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-decoration: none;
  color: var(--ink);
  white-space: nowrap;
}

.brand span { color: var(--secondary); font-weight: 600; }

.nav {
  display: flex;
  gap: 22px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 600;
}

.nav a { text-decoration: none; color: var(--ink); }
.nav a[aria-current="page"] { color: var(--accent); }

.nav-toggle {
  display: none;
  border: 1px solid var(--border);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 650;
  padding: 8px 12px;
  cursor: pointer;
}

/* Instrument */

.instrument-band {
  background: var(--panel);
  color: var(--display);
  padding: 48px 0 56px;
}

.instrument-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 28px;
  align-items: start;
}

.stopwatch-main { grid-column: span 9; min-width: 0; }

.ops-rail {
  grid-column: span 3;
  border-left: 1px solid rgba(211, 216, 213, 0.22);
  padding-left: 22px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.45;
}

.kicker {
  font-family: var(--font-sans);
  font-size: 12px;
  letter-spacing: 0.18em;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 10px;
}

.instrument-band h1 {
  color: var(--display);
  font-size: clamp(28px, 3vw, 40px);
  margin-bottom: 18px;
}

.time-display {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(38px, 8.4vw, 108px);
  letter-spacing: 0.02em;
  line-height: 1;
  white-space: nowrap;
  overflow: hidden;
  color: var(--display);
  margin: 8px 0 28px;
}

.control-rail {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.btn {
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  border: 1px solid transparent;
  min-height: 46px;
  padding: 0 18px;
  cursor: pointer;
  background: var(--accent);
  color: #1a140c;
}

.btn:hover { filter: brightness(1.05); }

.btn:disabled {
  opacity: 0.38;
  cursor: not-allowed;
  filter: none;
}

.btn-ghost {
  background: transparent;
  color: var(--display);
  border-color: rgba(246, 244, 233, 0.35);
}

.btn-light {
  background: var(--paper);
  color: var(--ink);
  border-color: var(--border);
}

.btn-touch { min-width: 88px; }

.ops-label {
  color: var(--secondary);
  letter-spacing: 0.14em;
  font-size: 10px;
  margin: 14px 0 4px;
}

.ops-rail .ops-label:first-child { margin-top: 0; }

.ops-value {
  color: var(--display);
  font-size: 13px;
}

.note {
  margin-top: 22px;
  color: rgba(246, 244, 233, 0.72);
  font-family: var(--font-serif);
  font-size: 14px;
  line-height: 1.55;
}

.kbd-help {
  margin-top: 16px;
  color: rgba(246, 244, 233, 0.7);
  font-size: 11px;
}

kbd {
  font-family: var(--font-mono);
  border: 1px solid rgba(246, 244, 233, 0.28);
  padding: 1px 5px;
  font-size: 10px;
}

/* Sections */

.section {
  padding: 64px 0;
  border-top: 1px solid var(--border);
}

.section h2 { font-size: clamp(26px, 3vw, 34px); }

.lede {
  max-width: 62ch;
  color: #33414b;
}

/* Lap ledger */

.ledger-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: end;
  flex-wrap: wrap;
  margin-bottom: 18px;
}

.table-scroll { overflow-x: auto; }

.ledger {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-mono);
  font-size: 14px;
  background: var(--paper);
  min-width: 560px;
}

.ledger th,
.ledger td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  font-variant-numeric: tabular-nums;
}

.ledger th {
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  font-weight: 700;
  background: #e8ebe7;
}

.ledger-empty,
.limit-note,
.status-line {
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--secondary);
  margin-top: 10px;
}

.limit-note { color: #8a4b1f; }

/* Analysis */

.metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  margin: 28px 0;
}

.metric {
  background: var(--paper);
  padding: 18px 16px 16px;
}

.metric span {
  display: block;
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.14em;
  font-weight: 700;
  color: var(--secondary);
  margin-bottom: 8px;
}

.metric strong {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 650;
}

.chart-frame {
  background: var(--paper);
  border: 1px solid var(--border);
  padding: 12px 12px 4px;
}

.chart-frame svg { display: block; width: 100%; height: auto; }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Countdown */

.countdown-panel {
  background: var(--paper);
  border: 1px solid var(--border);
  padding: 28px;
}

.cd-display {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(36px, 6vw, 64px);
  letter-spacing: 0.04em;
  margin: 8px 0 22px;
}

.cd-inputs {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 18px;
}

.field label {
  display: block;
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  font-weight: 700;
  margin-bottom: 6px;
}

.field input {
  width: 100%;
  font-family: var(--font-mono);
  font-size: 20px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--ink);
}

.cd-message {
  min-height: 1.4em;
  font-family: var(--font-sans);
  font-size: 14px;
  margin: 14px 0 0;
}

.cd-message.is-error { color: #8a341f; }
.cd-message.is-done { color: #2f6b4f; }
.cd-message.is-info { color: var(--secondary); }

.sound-row {
  margin-top: 16px;
  font-family: var(--font-sans);
  font-size: 14px;
  display: flex;
  gap: 8px;
  align-items: flex-start;
}

.fine-print {
  font-size: 14px;
  color: #4a5963;
}

/* Presets */

.preset-stack { display: grid; gap: 8px; }

.preset-strip {
  display: grid;
  grid-template-columns: 180px 110px 1fr auto;
  gap: 16px;
  align-items: center;
  border: 1px solid var(--border);
  background: var(--paper);
  padding: 14px 16px;
  width: 100%;
  text-align: left;
  color: inherit;
  cursor: pointer;
  font: inherit;
}

.preset-strip:hover { border-color: var(--secondary); }

.preset-strip b {
  font-family: var(--font-sans);
  font-size: 15px;
}

.preset-strip .dur {
  font-family: var(--font-mono);
  color: var(--secondary);
}

.preset-strip p {
  margin: 0;
  font-size: 15px;
}

/* Instructions */

.two-col {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
}

.steps {
  margin: 0;
  padding-left: 22px;
}

.steps li { margin-bottom: 12px; }

.example-box {
  background: var(--paper);
  border: 1px solid var(--border);
  padding: 18px 20px;
  font-family: var(--font-mono);
  font-size: 14px;
}

.example-box dt {
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--secondary);
  margin-top: 12px;
}

.example-box dt:first-child { margin-top: 0; }

.example-box dd { margin: 4px 0 0; }

/* Use cases */

.usecase-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 0;
  border-top: 1px solid var(--border);
}

.usecase {
  padding: 22px 20px 18px 0;
  border-bottom: 1px solid var(--border);
}

.usecase:nth-child(even) {
  padding-left: 28px;
}

.usecase h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.usecase p { font-size: 16px; margin-bottom: 0.5em; }

.tag {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--secondary);
}

/* Reference ledger */

.ref-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--paper);
}

.ref-table th,
.ref-table td {
  border-bottom: 1px solid var(--border);
  padding: 14px 16px;
  vertical-align: top;
  text-align: left;
}

.ref-table th {
  font-family: var(--font-sans);
  width: 28%;
  font-size: 14px;
}

.ref-table td { font-size: 16px; }

/* Articles list */

.article-list {
  display: grid;
  gap: 0;
}

.article-list a {
  display: block;
  padding: 18px 0;
  border-bottom: 1px solid var(--border);
  text-decoration: none;
}

.article-list a strong {
  display: block;
  font-family: var(--font-sans);
  font-size: 18px;
  margin-bottom: 4px;
}

.article-list a span {
  color: #4a5963;
  font-size: 16px;
}

/* About / contact */

.contact-block {
  font-family: var(--font-sans);
  line-height: 1.7;
}

.contact-block a { color: var(--ink); }

/* Footer */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 36px 0 48px;
  font-family: var(--font-sans);
  font-size: 14px;
}

.footer-id {
  font-weight: 700;
  margin-bottom: 12px;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 0;
  margin-bottom: 12px;
}

.footer-nav a { text-decoration: none; }
.footer-nav span { margin: 0 8px; color: var(--border); }

/* Article pages */

.article-body {
  padding: 48px 0 72px;
  font-size: 19px;
}

.article-body h1 { font-size: clamp(32px, 4vw, 44px); margin-bottom: 12px; }

.article-body h2 { margin-top: 1.6em; }

.crumb {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--secondary);
  margin-bottom: 18px;
}

.article-tools {
  margin-top: 2em;
  padding-top: 1em;
  border-top: 1px solid var(--border);
  font-family: var(--font-sans);
  font-size: 16px;
}

/* Mobile */

@media (max-width: 760px) {
  .nav {
    display: none;
    position: absolute;
    top: 62px;
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 12px 16px 18px;
    gap: 12px;
  }

  .nav.is-open { display: flex; }

  .nav-toggle { display: inline-flex; }

  .instrument-grid { grid-template-columns: 1fr; }

  .stopwatch-main,
  .ops-rail {
    grid-column: auto;
  }

  .ops-rail {
    border-left: 0;
    padding-left: 0;
    border-top: 1px solid rgba(211, 216, 213, 0.22);
    padding-top: 18px;
  }

  .control-rail .btn { min-height: 52px; flex: 1 1 40%; }

  .metrics { grid-template-columns: 1fr 1fr; }

  .two-col,
  .usecase-grid { grid-template-columns: 1fr; }

  .usecase:nth-child(even) { padding-left: 0; }

  .preset-strip {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .cd-inputs { grid-template-columns: 1fr; }

  .time-display { font-size: clamp(38px, 11vw, 64px); }
}