/* ============================================================
   Joint Actuator Explorer — design tokens & layout
   Inspired by the Batemo Cell Explorer aesthetic:
   light, technical, generous whitespace, teal/blue primary,
   orange selection accent, precise typography.
   ============================================================ */

:root {
  /* Color */
  --c-bg:           #ffffff;
  --c-bg-alt:       #f5f7fa;
  --c-bg-tint:      #eef2f6;
  --c-border:       #dde3ea;
  --c-border-strong:#c6cfd9;
  --c-text:         #0f172a;
  --c-text-muted:   #475569;
  --c-text-subtle:  #64748b;

  --c-primary:      #0e7490;       /* teal-700 */
  --c-primary-700:  #155e75;
  --c-primary-50:   #ecfeff;
  --c-primary-100:  #cffafe;
  --c-accent:       #ea580c;       /* orange-600 — selection / pin */
  --c-accent-50:    #fff7ed;

  --c-ok:           #15803d;
  --c-warn:         #b45309;

  /* Type */
  --f-sans: 'Inter', 'Noto Sans SC', system-ui, -apple-system, 'Segoe UI', Roboto, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --f-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

  /* Layout */
  --container: 1280px;
  --radius:    8px;
  --radius-sm: 6px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04), 0 1px 3px rgba(15, 23, 42, 0.06);
  --shadow:    0 4px 12px rgba(15, 23, 42, 0.06), 0 2px 4px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 18px 48px rgba(15, 23, 42, 0.10), 0 8px 16px rgba(15, 23, 42, 0.06);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--f-sans);
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: var(--c-primary); text-decoration: none; }
a:hover { color: var(--c-primary-700); text-decoration: underline; }
button { font-family: inherit; }
input, select, button { font-size: 14px; }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header ---------- */
.site-header {
  border-bottom: 1px solid var(--c-border);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(8px);
  position: sticky;
  top: 0;
  z-index: 50;
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--c-text);
  font-weight: 600;
  letter-spacing: -0.01em;
}
.brand:hover { text-decoration: none; }
.brand__mark {
  width: 22px; height: 22px;
  background: linear-gradient(135deg, var(--c-primary) 0%, #06b6d4 100%);
  border-radius: 5px;
  position: relative;
}
.brand__mark::after {
  content: "";
  position: absolute; inset: 5px;
  background: white;
  border-radius: 2px;
  opacity: 0.85;
}
.brand__name { font-size: 15px; }
.site-header__right {
  display: flex;
  align-items: center;
  gap: 20px;
}
.site-nav {
  display: flex;
  gap: 28px;
  font-size: 14px;
}
.site-nav a {
  color: var(--c-text-muted);
  font-weight: 500;
}
.site-nav a:hover { color: var(--c-primary); text-decoration: none; }

/* Language toggle */
.lang-toggle {
  display: inline-flex;
  background: var(--c-bg-tint);
  border-radius: var(--radius-sm);
  padding: 3px;
  gap: 2px;
}
.lang-toggle button {
  background: transparent;
  border: 0;
  padding: 4px 10px;
  font-size: 12px;
  font-weight: 600;
  color: var(--c-text-muted);
  border-radius: 4px;
  cursor: pointer;
  min-width: 32px;
  transition: background 120ms, color 120ms;
}
.lang-toggle button:hover { color: var(--c-text); }
.lang-toggle button.is-active {
  background: white;
  color: var(--c-primary);
  box-shadow: var(--shadow-sm);
}

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(180deg, var(--c-bg-alt) 0%, var(--c-bg) 100%);
  border-bottom: 1px solid var(--c-border);
  padding: 64px 0 48px;
}
.hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 48px;
  align-items: end;
}
.eyebrow {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--c-primary);
  margin: 0 0 12px;
}
.hero__title {
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  font-weight: 700;
  margin: 0 0 16px;
  color: var(--c-text);
}
.accent { color: var(--c-primary); }
.hero__sub {
  font-size: 17px;
  line-height: 1.55;
  color: var(--c-text-muted);
  max-width: 640px;
  margin: 0 0 24px;
}
.hero__search input {
  width: 100%;
  max-width: 560px;
  padding: 12px 14px;
  border: 1px solid var(--c-border-strong);
  border-radius: var(--radius);
  background: white;
  font-size: 14px;
  outline: none;
  transition: border-color 120ms, box-shadow 120ms;
}
.hero__search input:focus {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px var(--c-primary-100);
}

.hero__stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.stat {
  background: white;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow-sm);
}
.stat__value {
  font-family: var(--f-mono);
  font-size: 24px;
  font-weight: 600;
  color: var(--c-text);
  letter-spacing: -0.01em;
}
.stat__label {
  font-size: 12px;
  color: var(--c-text-muted);
  margin-top: 4px;
}

/* ---------- Explorer ---------- */
.explorer {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 32px;
  padding: 40px 24px 80px;
}

/* Sidebar filters */
.filters {
  position: sticky;
  top: 80px;
  align-self: start;
  background: white;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow-sm);
  max-height: calc(100vh - 100px);
  overflow-y: auto;
}
.filters__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 20px;
}
.filters__head h2 {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--c-text-muted);
  margin: 0;
}
.link {
  background: none;
  border: 0;
  color: var(--c-primary);
  font-size: 12px;
  cursor: pointer;
  padding: 0;
}
.link:hover { text-decoration: underline; }

.filter-group {
  border-top: 1px solid var(--c-border);
  padding: 16px 0;
}
.filter-group:first-of-type { border-top: 0; padding-top: 0; }
.filter-group h3 {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--c-text-subtle);
  margin: 0 0 10px;
  font-weight: 600;
}
.filter-group__body {
  display: flex;
  flex-direction: column;
  gap: 6px;
  max-height: 180px;
  overflow-y: auto;
  padding-right: 4px;
}
.filter-group__body--toggle {
  max-height: none;
  overflow: visible;
  padding-right: 0;
}
.checkbox {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--c-text);
  cursor: pointer;
  padding: 4px 6px;
  border-radius: var(--radius-sm);
  user-select: none;
}
.checkbox:hover { background: var(--c-bg-tint); }
.checkbox input { accent-color: var(--c-primary); margin: 0; }
.checkbox .count {
  margin-left: auto;
  color: var(--c-text-subtle);
  font-family: var(--f-mono);
  font-size: 11px;
}

/* Range slider (dual-handle) */
.range {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.range__track {
  position: relative;
  height: 28px;
}
.range__rail {
  position: absolute;
  top: 13px;
  left: 0; right: 0;
  height: 3px;
  background: var(--c-border);
  border-radius: 2px;
}
.range__fill {
  position: absolute;
  top: 13px;
  height: 3px;
  background: var(--c-primary);
  border-radius: 2px;
}
.range__track input[type="range"] {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 28px;
  background: none;
  appearance: none;
  pointer-events: none;
  margin: 0;
}
.range__track input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  pointer-events: auto;
  width: 16px; height: 16px;
  background: white;
  border: 2px solid var(--c-primary);
  border-radius: 50%;
  cursor: grab;
  margin-top: -6px;
}
.range__track input[type="range"]::-moz-range-thumb {
  pointer-events: auto;
  width: 16px; height: 16px;
  background: white;
  border: 2px solid var(--c-primary);
  border-radius: 50%;
  cursor: grab;
}
.range__values {
  display: flex;
  justify-content: space-between;
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--c-text-muted);
}

/* Visualization pane */
.viz {
  background: white;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  min-height: 600px;
  display: flex;
  flex-direction: column;
}
.viz__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  border-bottom: 1px solid var(--c-border);
}
.tabs {
  display: flex;
  gap: 4px;
  background: var(--c-bg-tint);
  padding: 4px;
  border-radius: var(--radius);
}
.tab {
  background: transparent;
  border: 0;
  padding: 7px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--c-text-muted);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 120ms, color 120ms;
}
.tab:hover { color: var(--c-text); }
.tab.is-active {
  background: white;
  color: var(--c-primary);
  box-shadow: var(--shadow-sm);
}
.viz__meta {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--c-text-muted);
}
.viz__body {
  flex: 1;
  position: relative;
}
.view {
  display: none;
  padding: 20px;
  height: 100%;
}
.view.is-active { display: block; }
.plot {
  width: 100%;
  height: 540px;
}
.plot--small {
  height: 520px;
}

/* Stacked scatter (rated torque vs weight, then peak torque vs weight) */
.scatter-grid {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.scatter-card {
  background: white;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 14px 14px 8px;
}
.scatter-card__title {
  margin: 0 0 4px;
  font-size: 13px;
  font-weight: 600;
  color: var(--c-text);
  text-transform: none;
  letter-spacing: 0;
}
.viz__note {
  margin: 8px 0 0;
  font-size: 12px;
  color: var(--c-text-subtle);
}

/* Spec table */
.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius);
}
.spec-table,
.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}
.spec-table th,
.spec-table td,
.compare-table th,
.compare-table td {
  padding: 10px 12px;
  text-align: left;
  border-bottom: 1px solid var(--c-border);
  white-space: nowrap;
}
.spec-table th {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--c-text-muted);
  font-weight: 600;
  cursor: pointer;
  user-select: none;
  background: var(--c-bg-alt);
  position: sticky;
  top: 0;
  z-index: 1;
}
.spec-table th:hover { color: var(--c-primary); }
.spec-table th.num,
.spec-table td.num { text-align: right; font-family: var(--f-mono); }
.spec-table tbody tr:hover { background: var(--c-bg-tint); }
.spec-table tbody tr.is-pinned {
  background: var(--c-accent-50);
}
.spec-table .pin-btn {
  background: none;
  border: 1px solid var(--c-border-strong);
  border-radius: var(--radius-sm);
  width: 24px; height: 24px;
  cursor: pointer;
  color: var(--c-text-subtle);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 120ms;
}
.spec-table tr.is-pinned .pin-btn,
.spec-table .pin-btn:hover {
  background: var(--c-accent);
  border-color: var(--c-accent);
  color: white;
}

/* ---------- Compare drawer ---------- */
.drawer {
  position: fixed;
  left: 0; right: 0;
  bottom: 0;
  background: white;
  border-top: 1px solid var(--c-border-strong);
  box-shadow: var(--shadow-lg);
  z-index: 60;
  max-height: 65vh;
  display: flex;
  flex-direction: column;
  transition: transform 200ms ease;
}
.drawer.is-collapsed { transform: translateY(calc(100% - 56px)); }
.drawer__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  border-bottom: 1px solid var(--c-border);
}
.drawer__head h2 {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--c-text-muted);
  margin: 0;
}
.drawer__sub {
  font-size: 12px;
  color: var(--c-text-subtle);
  margin: 2px 0 0;
}
.drawer__actions {
  display: flex;
  gap: 8px;
  align-items: center;
}
.drawer__body {
  overflow: auto;
  padding: 16px 24px 24px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--c-border-strong);
  background: white;
  font-size: 13px;
  color: var(--c-text);
  cursor: pointer;
  transition: all 120ms;
}
.btn:hover { border-color: var(--c-primary); color: var(--c-primary); }
.btn--ghost { background: transparent; }
.btn--icon {
  padding: 4px 10px;
  font-size: 16px;
  line-height: 1;
}

.compare-table th,
.compare-table td {
  border-bottom: 1px solid var(--c-border);
  padding: 8px 12px;
  vertical-align: top;
}
.compare-table th:first-child {
  width: 200px;
  font-weight: 500;
  color: var(--c-text-muted);
  background: var(--c-bg-alt);
  position: sticky;
  left: 0;
  text-transform: none;
  letter-spacing: 0;
  font-size: 12px;
}
.compare-table thead th {
  font-size: 13px;
  font-weight: 600;
  color: var(--c-text);
  background: var(--c-bg-alt);
}
.compare-table .meta-row {
  background: var(--c-bg-alt);
}
.compare-table .col-best { color: var(--c-ok); font-weight: 600; }
.compare-table .col-worst { color: var(--c-warn); }
.compare-table .col-remove {
  color: var(--c-text-subtle);
  background: none;
  border: 0;
  cursor: pointer;
  font-size: 14px;
}
.compare-table .col-remove:hover { color: var(--c-accent); }

#curve-chart {
  width: 100%;
  height: 360px;
  margin-top: 16px;
  background: var(--c-bg-alt);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
}

/* ---------- Glossary ---------- */
.glossary {
  border-top: 1px solid var(--c-border);
  background: white;
  padding: 64px 0;
}
.glossary__inner { max-width: 1080px; margin: 0 auto; }
.glossary h2 {
  font-size: 26px;
  letter-spacing: -0.01em;
  margin: 0 0 8px;
  color: var(--c-text);
}
.glossary__intro {
  color: var(--c-text-muted);
  font-size: 15px;
  line-height: 1.55;
  max-width: 720px;
  margin: 0 0 28px;
}
.glossary__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin: 0;
}
.glossary__item {
  background: var(--c-bg-alt);
  border: 1px solid var(--c-border);
  border-left: 3px solid var(--c-primary);
  border-radius: var(--radius);
  padding: 16px 18px;
  transition: border-color 120ms, transform 120ms;
}
.glossary__item:hover {
  border-left-color: var(--c-accent);
  transform: translateY(-1px);
}
.glossary__term {
  font-weight: 600;
  font-size: 15px;
  color: var(--c-text);
  margin: 0 0 6px;
  line-height: 1.3;
}
.glossary__desc {
  color: var(--c-text-muted);
  font-size: 13.5px;
  line-height: 1.55;
  margin: 0;
}
.naming__title {
  font-size: 20px;
  letter-spacing: -0.01em;
  margin: 36px 0 8px;
  color: var(--c-text);
}
.naming__line {
  margin: 8px 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--c-text);
}
.naming__line code {
  background: var(--c-bg-alt);
  border: 1px solid var(--c-border);
  border-radius: 4px;
  padding: 2px 8px;
  font-size: 13px;
  margin-left: 6px;
}
.naming__sub {
  font-size: 15px;
  font-weight: 600;
  margin: 18px 0 8px;
  color: var(--c-text);
}
.naming__list {
  margin: 0 0 8px;
  padding-left: 20px;
  color: var(--c-text-muted);
  font-size: 13.5px;
  line-height: 1.7;
}
.naming__list li { margin: 0 0 4px; }

/* ---------- About / Footer ---------- */
.about {
  border-top: 1px solid var(--c-border);
  background: var(--c-bg-alt);
  padding: 56px 0;
}
.about__inner { max-width: 760px; }
.about h2 {
  font-size: 24px;
  letter-spacing: -0.01em;
  margin: 0 0 12px;
}
.about h3 {
  font-size: 16px;
  letter-spacing: 0;
  margin: 28px 0 8px;
  color: var(--c-text);
}
.about p {
  color: var(--c-text-muted);
  font-size: 16px;
  line-height: 1.6;
  margin: 0;
}
.about code {
  font-family: var(--f-mono);
  background: var(--c-bg-tint);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 14px;
}
.about__contact-list {
  margin: 8px 0 0;
  padding-left: 20px;
  color: var(--c-text-muted);
  font-size: 15px;
  line-height: 1.7;
}
.about__contact-list li { margin: 6px 0; }
.about__email {
  font-family: var(--f-mono);
  font-size: 14px;
  background: white;
  border: 1px solid var(--c-border);
  padding: 1px 8px;
  border-radius: 4px;
}
.about__email:hover { background: var(--c-primary-50); border-color: var(--c-primary); }

.site-footer {
  border-top: 1px solid var(--c-border);
  padding: 24px 0;
  font-size: 13px;
  color: var(--c-text-muted);
}
.site-footer__inner {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .hero__inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .explorer {
    grid-template-columns: 1fr;
  }
  .filters {
    position: static;
    max-height: none;
  }
  .filter-group__body { max-height: none; }
}
@media (max-width: 900px) {
  .glossary__grid { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .site-header__right { gap: 12px; }
  .site-nav { gap: 14px; font-size: 13px; }
  .lang-toggle button { padding: 3px 8px; font-size: 11px; min-width: 28px; }
  .hero { padding: 40px 0 32px; }
  .stat__value { font-size: 20px; }
  .plot { height: 380px; }
  .glossary { padding: 48px 0; }
  .glossary h2 { font-size: 22px; }
}