@import url('https://fonts.googleapis.com/css2?family=DM+Mono:wght@400;500&family=Manrope:wght@400;600;700&display=swap');

:root {
  --ink: #14231f;
  --muted: #66736d;
  --paper: #f2f0e8;
  --panel: rgba(255, 255, 252, .82);
  --line: rgba(20, 35, 31, .14);
  --accent: #ed5b2f;
  --water: #0d7168;
  --shadow: 0 18px 50px rgba(29, 50, 43, .11);
}

* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; }
body {
  color: var(--ink);
  background:
    radial-gradient(circle at 74% 10%, rgba(246, 169, 89, .22), transparent 28rem),
    linear-gradient(130deg, #e5eee8 0%, var(--paper) 52%, #eee6d9 100%);
  font-family: "Manrope", sans-serif;
}
button, input { font: inherit; }
button {
  border: 1px solid var(--line); border-radius: 7px; background: rgba(255,255,255,.7);
  color: var(--ink); cursor: pointer; padding: .58rem .7rem; transition: .16s ease;
}
button:hover { border-color: var(--water); transform: translateY(-1px); }
button.active { background: var(--ink); color: white; }

.masthead {
  height: 94px; padding: 17px 28px; display: flex; align-items: center; justify-content: space-between;
  border-bottom: 1px solid var(--line);
}
h1 { font-size: clamp(1.8rem, 3vw, 2.8rem); letter-spacing: -.065em; line-height: .92; margin: 4px 0 0; }
h2 { font-size: .77rem; letter-spacing: .09em; text-transform: uppercase; margin: 0 0 12px; }
.eyebrow { color: var(--water); font: 500 .67rem "DM Mono", monospace; letter-spacing: .12em; text-transform: uppercase; }
.status { font: 500 .7rem "DM Mono", monospace; display: flex; align-items: center; gap: 8px; }
.status span { width: 8px; height: 8px; border-radius: 50%; background: #43a673; box-shadow: 0 0 0 4px rgba(67,166,115,.15); }
.status.loading span { background: #dc963e; animation: pulse 1.1s infinite; }
.status.error span { background: #c63d31; }
@keyframes pulse { 50% { opacity: .35; } }

main { display: grid; grid-template-columns: 230px minmax(400px, 1fr) 230px; align-items: start; gap: 16px; padding: 16px; min-height: calc(100vh - 94px); }
.panel, .stage { border: 1px solid var(--line); border-radius: 12px; background: var(--panel); box-shadow: var(--shadow); backdrop-filter: blur(12px); }
.panel { overflow: visible; }
.panel section { padding: 18px; border-bottom: 1px solid var(--line); }
.controls section:first-child { padding-top: 20px; }
.controls h2 { font-size: .7rem; }
.controls button { padding: .44rem .58rem; font-size: .72rem; }
.controls .field { font-size: .72rem; }
.controls .hint, .controls .mode-note { font-size: .67rem; }
.preset-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 7px; }
.preset-grid .wide { grid-column: 1 / -1; }
.label-row { display: flex; justify-content: space-between; }
.label-row output { font: 500 .72rem "DM Mono", monospace; }
input[type="range"] { width: 100%; height: 18px; accent-color: var(--accent); cursor: ew-resize; }
input[type="range"]::-webkit-slider-runnable-track { height: 5px; border-radius: 3px; background: rgba(20,35,31,.18); }
input[type="range"]::-webkit-slider-thumb { width: 16px; height: 16px; margin-top: -5.5px; border: 2px solid white; border-radius: 50%; background: var(--accent); box-shadow: 0 1px 4px rgba(20,35,31,.3); -webkit-appearance: none; }
input[type="range"]::-moz-range-track { height: 5px; border-radius: 3px; background: rgba(20,35,31,.18); }
input[type="range"]::-moz-range-thumb { width: 13px; height: 13px; border: 2px solid white; border-radius: 50%; background: var(--accent); box-shadow: 0 1px 4px rgba(20,35,31,.3); }
.stepper, .segmented { display: grid; grid-template-columns: repeat(4, 1fr); gap: 5px; margin-top: 9px; }
.segmented { grid-template-columns: 1fr 1fr; }
.plot-options { display: grid; grid-template-columns: 1fr 1fr; gap: 5px; }
.plot-options button { padding-inline: .35rem; font-size: .65rem; }
.plot-options button.active { background: var(--ink); color: white; }
.field { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-top: 13px; color: var(--muted); font-size: .76rem; }
.field input { width: 78px; border: 1px solid var(--line); border-radius: 6px; padding: 6px; background: white; color: var(--ink); }
.hint { color: var(--muted); font-size: .71rem; line-height: 1.6; padding: 6px 18px 18px; }
.stage { position: relative; overflow: hidden; min-width: 0; aspect-ratio: 4 / 3; background: rgba(248,249,243,.72); }
#flowCanvas { display: block; width: 100%; height: 100%; touch-action: none; cursor: crosshair; }
#tracerCanvas { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; }
.legend { position: absolute; left: 16px; bottom: 58px; display: flex; gap: 12px; font: .65rem "DM Mono", monospace; color: var(--muted); background: rgba(255,255,255,.76); padding: 7px 9px; border-radius: 5px; }
.legend-item { display: inline-flex; align-items: center; gap: 7px; }
.legend-item i { display: inline-block; width: 24px; border-top: 2px solid var(--water); }
.legend-item .potential-key { border-color: var(--accent); }
.metric { margin-top: 13px; }
.metric span { color: var(--muted); font-size: .72rem; display: block; }
.metric strong { font: 500 clamp(2.5rem, 5vw, 4rem) "DM Mono", monospace; letter-spacing: -.08em; color: var(--accent); }
.matrix { display: grid; grid-template-columns: 1fr 1fr; gap: 2px; background: var(--ink); border: 7px solid var(--ink); border-radius: 5px; }
.matrix span { color: white; text-align: center; padding: 8px 2px; font: .72rem "DM Mono", monospace; background: #263a34; }
dl { margin: 0; }
dl div { display: flex; justify-content: space-between; padding: 7px 0; border-bottom: 1px dotted var(--line); }
dt, dd { font-size: .72rem; margin: 0; }
dt { color: var(--muted); }
.privacy { background: rgba(13,113,104,.08); }
.credit { background: rgba(237,91,47,.07); }
.privacy p, .credit p { color: var(--muted); font-size: .7rem; line-height: 1.55; margin: 0; }

@media (max-width: 980px) {
  main { grid-template-columns: 230px 1fr; height: auto; }
  .stage { min-height: 0; }
  .readout { grid-column: 1 / -1; display: grid; grid-template-columns: repeat(4, 1fr); }
  .readout section { border-bottom: 0; border-right: 1px solid var(--line); }
}
@media (max-width: 680px) {
  .masthead { height: 82px; padding: 14px 16px; }
  main { display: flex; flex-direction: column; height: auto; padding: 10px; }
  .controls { display: grid; grid-template-columns: 1fr 1fr; }
  .controls .hint { grid-column: 1 / -1; }
  .stage { min-height: 0; order: -1; }
  .readout { display: grid; grid-template-columns: 1fr 1fr; }
}
.vertex-picker { display: grid; grid-template-columns: 30px 48px 30px; gap: 4px; }
.vertex-picker button { padding: 5px; }
.field .vertex-picker input { width: 48px; text-align: center; }

.brand { display: flex; align-items: center; gap: 14px; }
.brand-icon { width: 78px; height: 62px; overflow: visible; }
.wind-line { fill: none; stroke: var(--water); stroke-width: 3; stroke-linecap: round; }
.body-mark { fill: var(--accent); stroke: var(--ink); stroke-width: 2.5; stroke-linejoin: round; }
.brand-copy h1 { margin: 0; }
.brand-copy p { margin: 6px 0 0; color: var(--water); font: 600 .72rem "Manrope", sans-serif; letter-spacing: .025em; }
.masthead-meta { align-self: stretch; display: flex; flex-direction: column; align-items: flex-end; justify-content: space-between; padding: 3px 0; }
.masthead-meta > strong { font: 600 .9rem "Manrope", sans-serif; letter-spacing: .025em; }
@media (max-width: 680px) {
  .brand-icon { width: 58px; height: 48px; }
  .brand-copy p { max-width: 220px; font-size: .56rem; line-height: 1.35; }
  .masthead-meta > strong { font-size: .72rem; }
}
.preset-grid button.active { background: #d8dcda; color: var(--ink); border-color: #aab2ae; }
.field.disabled { opacity: .42; pointer-events: none; }
.hidden { display: none !important; }
.origin-note { margin-top: 13px; padding: 10px 12px; border-radius: 6px; background: rgba(20,35,31,.06); color: var(--muted); font: 500 .72rem "DM Mono", monospace; text-align: center; }
.zoom-controls { position: absolute; top: 14px; right: 14px; display: grid; grid-template-columns: 34px 34px; gap: 6px; }
.zoom-controls button { padding: 6px; background: rgba(255,255,255,.86); font: 500 1rem "DM Mono", monospace; box-shadow: 0 3px 12px rgba(20,35,31,.08); }
.formula { display: block; margin-top: 4px; color: var(--ink); font: 500 .72rem "DM Mono", monospace; }
.copy-latex { width: 100%; margin-top: 8px; background: rgba(13,113,104,.09); border-color: rgba(13,113,104,.28); font: 500 .7rem "DM Mono", monospace; }
.mode-note { margin: 12px 0 0; color: var(--muted); font-size: .68rem; line-height: 1.5; }
.import-section { margin-top: auto; }
.import-open { width: 100%; background: rgba(237,91,47,.08); border-color: rgba(237,91,47,.28); }
.import-dialog { width: min(520px, calc(100vw - 32px)); padding: 0; border: 1px solid var(--line); border-radius: 12px; color: var(--ink); background: #f8f7f1; box-shadow: 0 28px 90px rgba(20,35,31,.28); }
.import-dialog::backdrop { background: rgba(20,35,31,.42); backdrop-filter: blur(3px); }
.import-dialog form { padding: 22px; }
.dialog-heading { display: flex; justify-content: space-between; align-items: flex-start; }
.dialog-heading h2 { margin-top: 5px; font-size: 1rem; }
.import-dialog p { color: var(--muted); font-size: .75rem; line-height: 1.55; }
.import-dialog code { font-family: "DM Mono", monospace; color: var(--ink); }
.import-dialog textarea { width: 100%; resize: vertical; border: 1px solid var(--line); border-radius: 7px; padding: 12px; background: white; color: var(--ink); font: .76rem/1.55 "DM Mono", monospace; }
.file-field { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-top: 12px; color: var(--muted); font-size: .75rem; }
.file-field input { max-width: 260px; font-size: .7rem; }
.import-error { min-height: 1.2em; color: #a33128 !important; }
.dialog-actions { display: flex; justify-content: flex-end; gap: 8px; }
.solver-error { position: absolute; left: 16px; right: 16px; top: 14px; z-index: 4; display: flex; align-items: flex-start; justify-content: space-between; gap: 14px; padding: 12px 14px; border: 1px solid rgba(163,49,40,.28); border-radius: 8px; background: rgba(255,245,240,.95); box-shadow: 0 8px 28px rgba(70,25,20,.14); }
.solver-error strong { color: #8f2e26; font-size: .76rem; }
.solver-error p { margin: 3px 0 0; color: #70413b; font-size: .68rem; line-height: 1.4; }
.solver-error button { flex: 0 0 auto; padding: 5px 8px; font-size: .68rem; }