/* Airfoil RANS Surrogate -- modern, fluid theme.
   Fixes the previous monochrome pass's real readability problem: thin
   font-weights against a pure #000/#fff extreme cause halation and are hard
   to read. Near-black/near-white surfaces, proper body-copy weight (420+),
   a single restrained indigo accent, soft rounded corners, gentle elevation
   via shadow (light) / surface-step (dark) instead of shadow, smooth
   transitions. Categorical/sequential data encodings use the dataviz
   skill's validated palette (references/palette.md) again -- monochrome-only
   charts read as an afterthought once the rest of the site has color back. */

:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --surface-sunken: #f4f4f6;
  --ink: #17171b;
  --ink-secondary: #52525b;
  --ink-muted: #82828c;
  --border: #e6e6ea;
  --border-strong: #d4d4d9;

  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-wash: #eef0fd;
  --accent-ink: #ffffff;

  --shadow-sm: 0 1px 2px rgba(20, 20, 30, 0.05);
  --shadow-md: 0 2px 8px rgba(20, 20, 30, 0.06), 0 8px 24px rgba(20, 20, 30, 0.05);

  /* categorical -- dataviz skill default palette, slots 1-4 */
  --cat-1: #2a78d6;
  --cat-2: #1baf7a;
  --cat-3: #eda100;
  --cat-4: #4a3aa7;

  /* sequential ramp for field magnitude, light -> dark = low -> high */
  --seq-0: #e8f0fd;
  --seq-1: #9ec5f4;
  --seq-2: #6da7ec;
  --seq-3: #3987e5;
  --seq-4: #256abf;
  --seq-5: #184f95;
  --seq-6: #0d366b;

  --status-warning: #b45309;
  --status-warning-wash: #fef3e2;

  --font: -apple-system, "SF Pro Text", "Inter", "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, monospace;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --transition: 160ms cubic-bezier(0.4, 0, 0.2, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0b0e;
    --surface: #16161a;
    --surface-sunken: #1d1d22;
    --ink: #f2f2f4;
    --ink-secondary: #b4b4bc;
    --ink-muted: #7c7c86;
    --border: #26262c;
    --border-strong: #34343c;

    --accent: #818cf8;
    --accent-hover: #a5b4fc;
    --accent-wash: #1c1b3a;
    --accent-ink: #0b0b0e;

    --shadow-sm: none;
    --shadow-md: none;

    --cat-1: #3987e5;
    --cat-2: #199e70;
    --cat-3: #c98500;
    --cat-4: #9085e9;

    --seq-0: #10192b;
    --seq-1: #1c3a63;
    --seq-2: #275790;
    --seq-3: #3987e5;
    --seq-4: #5598e7;
    --seq-5: #86b6ef;
    --seq-6: #cde2fb;

    --status-warning: #f5b866;
    --status-warning-wash: #2a2013;
  }
}

* {
  box-sizing: border-box;
}
html,
body {
  margin: 0;
  padding: 0;
}
body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-weight: 420;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover {
  color: var(--accent-hover);
}

::selection {
  background: var(--accent);
  color: var(--accent-ink);
}

* {
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background-color: var(--border-strong);
  border-radius: 999px;
  border: 2px solid var(--bg);
  background-clip: padding-box;
}
::-webkit-scrollbar-thumb:hover {
  background-color: var(--ink-muted);
}

code,
pre,
.mono {
  font-family: var(--font-mono);
}
code {
  background: var(--surface-sunken);
  border-radius: 4px;
  padding: 2px 6px;
  font-size: 0.9em;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 32px;
}

/* ---------- nav ---------- */

.site-nav {
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.site-nav .brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.site-nav .brand:hover {
  color: var(--ink);
}
.site-nav .brand .thin {
  font-weight: 400;
  color: var(--ink-secondary);
}
.brand-mark {
  flex-shrink: 0;
  transition: transform var(--transition);
}
.site-nav .brand:hover .brand-mark {
  transform: translateX(2px) rotate(-4deg);
}
.site-nav .links {
  display: flex;
  gap: 8px;
}
.site-nav .links a {
  color: var(--ink-secondary);
  font-size: 14px;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
}
.site-nav .links a:hover {
  color: var(--ink);
  background: var(--surface-sunken);
}
.site-nav .links a.active {
  color: var(--accent);
  background: var(--accent-wash);
}

/* ---------- layout ---------- */

main {
  padding: 64px 0 120px;
  min-height: calc(100vh - 68px - 90px);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-wash);
  border-radius: 999px;
  padding: 6px 14px;
  margin-bottom: 24px;
}

.hero {
  position: relative;
  padding: 8px 0 40px;
  isolation: isolate;
}
.hero::before {
  content: "";
  position: absolute;
  top: -140px;
  right: -120px;
  width: 560px;
  height: 560px;
  background: radial-gradient(circle, var(--accent) 0%, transparent 70%);
  opacity: 0.14;
  filter: blur(50px);
  z-index: -1;
  pointer-events: none;
}
@media (prefers-color-scheme: dark) {
  .hero::before {
    opacity: 0.2;
  }
}
.hero h1 {
  font-size: clamp(36px, 5vw, 52px);
  font-weight: 650;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin: 0 0 24px;
  max-width: 780px;
}
.hero p.lede {
  font-size: 19px;
  font-weight: 420;
  color: var(--ink-secondary);
  max-width: 620px;
  margin: 0 0 36px;
  line-height: 1.6;
}

h1,
h2,
h3,
h4 {
  font-weight: 650;
  letter-spacing: -0.015em;
  color: var(--ink);
}
h1 {
  font-size: clamp(30px, 4vw, 40px);
}
h2 {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin: 56px 0 24px;
}
h3 {
  font-size: 19px;
  font-weight: 650;
  margin: 28px 0 10px;
}
p {
  color: var(--ink-secondary);
  font-weight: 420;
}

/* ---------- buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 24px;
  font-size: 14.5px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition), color var(--transition), border-color var(--transition);
  border: 1px solid transparent;
}
.btn:active {
  transform: scale(0.98);
}
.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
  box-shadow: var(--shadow-sm);
}
.btn-primary:hover {
  background: var(--accent-hover);
  box-shadow: var(--shadow-md);
}
.btn-secondary {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--border-strong);
}
.btn-secondary:hover {
  border-color: var(--ink-muted);
  background: var(--surface-sunken);
}
a.btn:hover {
  color: inherit;
}

/* ---------- cards ---------- */

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 26px;
  transition: box-shadow var(--transition), border-color var(--transition), transform var(--transition);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin: 28px 0;
}
.card-grid .card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
  transform: translateY(-3px);
}

.card-icon {
  display: inline-flex;
  color: var(--accent);
  margin-bottom: 12px;
}

.stat-tile .value {
  font-size: 32px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  color: var(--ink);
}
.stat-tile .label {
  font-size: 13px;
  font-weight: 500;
  color: var(--ink-muted);
  margin-top: 6px;
}

/* ---------- tables ---------- */

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14.5px;
  margin: 24px 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
th,
td {
  text-align: left;
  padding: 15px 18px;
  border-bottom: 1px solid var(--border);
  font-variant-numeric: tabular-nums;
  font-weight: 420;
}
th {
  color: var(--ink-muted);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--surface-sunken);
}
tr:last-child td {
  border-bottom: none;
}
tbody tr {
  transition: background var(--transition);
}
tbody tr:hover {
  background: var(--surface-sunken);
}
tr.highlight {
  background: var(--accent-wash);
}
tr.highlight:hover {
  background: var(--accent-wash);
}
tr.highlight td {
  font-weight: 650;
}
.swatch {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 3px;
  margin-right: 10px;
}

/* ---------- forms ---------- */

label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-secondary);
  margin-bottom: 8px;
}
input[type="text"],
input[type="number"],
select,
textarea {
  width: 100%;
  padding: 11px 14px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--ink);
  font-family: var(--font);
  font-size: 14.5px;
  transition: border-color var(--transition), box-shadow var(--transition);
}
input[type="text"]:focus,
select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-wash);
}
select {
  appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, var(--ink-muted) 50%), linear-gradient(135deg, var(--ink-muted) 50%, transparent 50%);
  background-position: calc(100% - 18px) center, calc(100% - 13px) center;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
}
input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}
.field {
  margin-bottom: 22px;
}
.field .range-value {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--ink-secondary);
  float: right;
  font-weight: 500;
}
.radio-row {
  display: flex;
  gap: 20px;
  margin-bottom: 14px;
}
.radio-row label {
  display: flex;
  align-items: center;
  gap: 7px;
  font-weight: 500;
  font-size: 14.5px;
  margin: 0;
  color: var(--ink);
}
input[type="radio"],
input[type="checkbox"] {
  accent-color: var(--accent);
}

/* ---------- badges / status ---------- */

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 11.5px;
  font-weight: 700;
}
.badge-accent {
  background: var(--accent);
  color: var(--accent-ink);
}

.warning-banner {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  background: var(--status-warning-wash);
  border: 1px solid color-mix(in srgb, var(--status-warning) 35%, transparent);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  font-size: 13.5px;
  font-weight: 420;
  color: var(--ink-secondary);
  margin-bottom: 16px;
}
.warning-banner .icon {
  color: var(--status-warning);
  font-weight: 700;
}

/* ---------- tool page ---------- */

.tool-layout {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 40px;
  align-items: start;
}
@media (max-width: 800px) {
  .tool-layout {
    grid-template-columns: 1fr;
  }
}

#field-canvas-wrap {
  position: relative;
}
#field-canvas {
  width: 100%;
  height: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}
.colorbar {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 14px;
  font-size: 12px;
  color: var(--ink-muted);
  font-family: var(--font-mono);
}
.colorbar-strip {
  flex: 1;
  height: 8px;
  border-radius: 999px;
  background: linear-gradient(to right, var(--seq-0), var(--seq-1), var(--seq-2), var(--seq-3), var(--seq-4), var(--seq-5), var(--seq-6));
}

.readout-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 24px;
}

/* ---------- files page ---------- */

.files-layout {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 32px;
  align-items: start;
}
@media (max-width: 800px) {
  .files-layout {
    grid-template-columns: 1fr;
  }
}
#file-tree {
  font-size: 13.5px;
  max-height: 70vh;
  overflow-y: auto;
  padding: 10px;
}
.file-row {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  white-space: nowrap;
  font-weight: 450;
  transition: background var(--transition);
}
.file-row:hover {
  background: var(--surface-sunken);
}
.file-row .icon {
  color: var(--ink-muted);
  width: 14px;
  flex-shrink: 0;
  font-family: var(--font-mono);
}
.file-row .size {
  margin-left: auto;
  color: var(--ink-muted);
  font-family: var(--font-mono);
  font-size: 11px;
}
#file-preview {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 420;
  white-space: pre-wrap;
  word-break: break-word;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  max-height: 70vh;
  overflow: auto;
  color: var(--ink);
}
.breadcrumbs {
  font-size: 13px;
  font-weight: 500;
  color: var(--ink-muted);
  margin-bottom: 16px;
}
.breadcrumbs a {
  color: var(--ink-secondary);
}
.breadcrumbs a:hover {
  color: var(--accent);
}

/* ---------- footer ---------- */

footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  font-size: 13px;
  font-weight: 450;
  color: var(--ink-muted);
}

/* ---------- gallery / media ---------- */

.media-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 24px;
  margin: 24px 0;
}
.media-grid figure {
  margin: 0;
}
.media-grid .frame {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border);
  background: #ffffff;
  box-shadow: var(--shadow-sm);
}
.media-grid img {
  width: 100%;
  display: block;
}
.media-grid figcaption {
  font-size: 13px;
  font-weight: 450;
  color: var(--ink-muted);
  margin-top: 12px;
}

.loading {
  color: var(--ink-muted);
  font-size: 13.5px;
  font-weight: 420;
}