/* Aero Hydro: interactive physics of sailing. Colors follow the CWO presentation. */
:root {
  --bg: #dcf0fa;
  --card: #ffffff;
  --border: #b9d9ea;
  --fg: #1d2747;
  --muted: #5b6785;
  --title: #e8702a;
  --accent: #6a3fb5;

  /* Physics colors: the same meaning on every page. */
  --werkelijk: #f08a24;  /* werkelijke wind */
  --vaart: #2e9e4f;      /* vaartwind */
  --schijn: #2f80ed;     /* schijnbare wind */
  --kracht: #d62828;     /* krachten */
  --drijf: #1554a8;      /* drijfkracht */
  --moment: #7b3fbf;     /* arm, moment, koppel */
  --water: #bfe3f5;
  --water-deep: #8cc8e6;
  --hull: #ffffff;
  --hull-line: #1d2747;
  --sail: #fdfdf8;
}

* { box-sizing: border-box; }

html { background: var(--bg); }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 17px/1.5 "Nunito Sans", system-ui, sans-serif;
  overflow-x: hidden;
}

a { color: var(--accent); }

/* Top bar */
.topbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  align-items: center;
  justify-content: space-between;
  max-width: 1180px;
  margin: 0 auto;
  padding: 14px 16px;
}
.brand { font-weight: 800; color: var(--title); text-decoration: none; font-size: 1.15rem; }
.chapters { display: flex; flex-wrap: wrap; gap: 6px; list-style: none; margin: 0; padding: 0; }
.chapters a {
  display: grid;
  place-items: center;
  min-width: 34px;
  height: 34px;
  padding: 0 8px;
  border-radius: 10px;
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--fg);
  font-weight: 700;
  text-decoration: none;
}
.chapters a[aria-current="page"] { background: var(--title); border-color: var(--title); color: #fff; }

/* Page header */
.page-head { max-width: 1180px; margin: 0 auto; padding: 8px 16px 0; }
.page-head h1 { color: var(--title); font-size: clamp(1.8rem, 5vw, 2.6rem); line-height: 1.15; margin: 0 0 4px; }
.page-head .vraag { font-size: 1.2rem; color: var(--accent); margin: 0; font-weight: 700; }

main { max-width: 1180px; margin: 0 auto; padding: 20px 16px 40px; display: grid; gap: 28px; grid-template-columns: minmax(0, 1fr); }

/* One visualization */
.viz {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 20px;
  scroll-margin-top: 12px;
}
.viz h2 { margin: 0; font-size: 1.45rem; color: var(--fg); }
.viz h2 .nr { color: var(--title); margin-right: 8px; }
.viz h2 .star { color: var(--title); font-size: 1rem; vertical-align: middle; margin-left: 6px; }
.viz .vraag { margin: 2px 0 14px; color: var(--accent); font-weight: 700; }

.viz-body { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 20px; align-items: start; }
.viz-body.wide { grid-template-columns: minmax(0, 1fr); }
.stage { position: relative; min-width: 0; }
.stage svg, .stage canvas { display: block; width: 100%; height: auto; border-radius: 12px; touch-action: pan-y; user-select: none; -webkit-user-select: none; }
.stage .sky { fill: #eef8fd; }
.stage .water { fill: var(--water); }

/* Controls */
.controls { display: grid; gap: 12px; align-content: start; }
/* Wide screens: the drawing stays in view next to long controls (class stick, core.js). */
.viz-body.stick > .stage { position: sticky; top: 16px; }
.controls.row { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }
.ctl { display: grid; gap: 2px; font-weight: 700; font-size: 0.95rem; }
.ctl .top { display: flex; justify-content: space-between; gap: 8px; }
.ctl output { color: var(--accent); font-variant-numeric: tabular-nums; white-space: nowrap; }
.ctl input[type="range"] { width: 100%; accent-color: var(--title); height: 28px; margin: 0; }

.seg { display: flex; flex-wrap: wrap; gap: 6px; }
.seg button, .btn {
  font: inherit;
  font-size: 0.92rem;
  font-weight: 700;
  border: 1px solid var(--border);
  background: #f2f8fc;
  color: var(--fg);
  border-radius: 10px;
  padding: 7px 12px;
  cursor: pointer;
}
.seg button[aria-pressed="true"] { background: var(--title); border-color: var(--title); color: #fff; }
.btn { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.secondary { background: #f2f8fc; color: var(--fg); border-color: var(--border); }
.btn:disabled { opacity: 0.5; cursor: default; }
.btns { display: flex; flex-wrap: wrap; gap: 8px; }

.check { display: flex; gap: 8px; align-items: center; font-weight: 700; font-size: 0.95rem; cursor: pointer; }
.check input { width: 18px; height: 18px; accent-color: var(--title); }

.readouts { display: grid; gap: 4px; background: #f2f8fc; border: 1px solid var(--border); border-radius: 12px; padding: 10px 12px; font-size: 0.95rem; }
.readouts:empty { display: none; }
.readout { display: flex; justify-content: space-between; gap: 10px; }
.readout b { font-variant-numeric: tabular-nums; }
.verdict { font-weight: 700; color: var(--accent); min-height: 1.5em; }
.verdict.good { color: var(--vaart); }
.verdict.bad { color: var(--kracht); }

.legend { display: flex; flex-wrap: wrap; gap: 4px 14px; list-style: none; margin: 0; padding: 0; font-size: 0.88rem; color: var(--muted); }
.legend li { display: flex; align-items: center; gap: 6px; }
.legend i { display: inline-block; width: 22px; height: 4px; border-radius: 2px; }

/* Text inside drawings */
.lbl { font: 700 14px "Nunito Sans", system-ui, sans-serif; paint-order: stroke; stroke: #fff; stroke-width: 4px; stroke-linejoin: round; }
.lbl.small { font-size: 12px; }
.lbl.big { font-size: 18px; }
.lbl.muted { fill: var(--muted); }
.pt-label { font: 800 13px "Nunito Sans", system-ui, sans-serif; paint-order: stroke; stroke: #fff; stroke-width: 4px; }

/* Extra explanation */
details.uitleg { margin-top: 14px; color: var(--muted); font-size: 0.95rem; }
details.uitleg summary { cursor: pointer; font-weight: 700; color: var(--accent); }
details.uitleg p { margin: 6px 0 0; max-width: 75ch; }

/* Chapter navigation at the bottom */
.pager { max-width: 1180px; margin: 0 auto; padding: 0 16px 40px; display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.pager a { font-weight: 700; text-decoration: none; background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 10px 16px; }

/* Home page */
.hero { max-width: 1180px; margin: 0 auto; padding: 24px 16px 4px; }
.hero h1 { color: var(--title); font-size: clamp(2.2rem, 7vw, 3.6rem); margin: 0; line-height: 1.1; }
.hero p { font-size: 1.2rem; color: var(--accent); font-weight: 700; margin: 6px 0 0; }
.chain { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin-top: 14px; font-weight: 700; }
.chain span { background: var(--card); border: 1px solid var(--border); border-radius: 999px; padding: 4px 12px; }
.toc { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.toc a { display: grid; gap: 6px; text-decoration: none; color: var(--fg); background: var(--card); border: 1px solid var(--border); border-radius: 18px; padding: 16px; transition: transform 0.15s, box-shadow 0.15s; }
.toc a:hover { transform: translateY(-2px); box-shadow: 0 6px 18px rgba(29, 39, 71, 0.12); }
.toc svg { width: 100%; height: auto; border-radius: 10px; background: #eef8fd; }
.toc h2 { margin: 0; font-size: 1.2rem; }
.toc h2 .nr { color: var(--title); margin-right: 6px; }
.toc p { margin: 0; color: var(--accent); font-weight: 700; font-size: 0.95rem; }
.toc ul { margin: 0; padding-left: 18px; color: var(--muted); font-size: 0.9rem; }

.keylegend { background: var(--card); border: 1px solid var(--border); border-radius: 18px; padding: 16px 20px; }
.keylegend h2 { margin: 0 0 8px; font-size: 1.1rem; }

footer { text-align: center; color: var(--muted); padding: 0 16px 32px; font-size: 0.9rem; }

/* On phones the drawings shrink to about half size: make the labels bigger to compensate. */
@media (max-width: 520px) {
  .stage .lbl, .stage .pt-label { font-size: 16px; }
  .stage .lbl.small { font-size: 14px; }
  .stage .lbl.big { font-size: 20px; }
}

.panel-switch { display: none; }
@media (max-width: 860px) {
  .viz-body { grid-template-columns: minmax(0, 1fr); }
  .viz { padding: 16px 14px; }
  /* Phones: no drawing taller than half the screen, and it stays at the top while you
     scroll through the controls (class stick, set in core.js when it fits). */
  .stage svg, .stage canvas { max-height: 50svh; }
  .panel-switch { display: block; margin-bottom: 6px; }
  .panel-switch .seg { justify-content: center; }
  .stage .panel-off { display: none !important; }
  .viz-body.stick > .stage { position: sticky; top: 0; z-index: 4; background: var(--card); padding: 6px 0 8px; box-shadow: 0 8px 8px -8px rgba(30, 40, 70, 0.25); }
}