:root { color-scheme: light dark; --bg: #f6f7f8; --card: #fff; --text: #1b2329; --muted: #5b6770; --line: #d8dee3; --accent: #0b6b57; --accent-soft: #e3f2ee; --warn-bg: #fff6e0; --warn: #6b4e00; --err: #a3271f; }
@media (prefers-color-scheme: dark) { :root { --bg: #12171b; --card: #1b2228; --text: #e8edf0; --muted: #a2afb8; --line: #333e46; --accent: #5ed1b6; --accent-soft: #17332d; --warn-bg: #33290f; --warn: #f1d58b; --err: #ff9a91; } }
* { box-sizing: border-box; }
/* Layout shift (measured 2026-11-09, desktop): the empty <main> painted before the scripts, then the page grew
   past the window, the scrollbar appeared and everything moved (CLS 0.438 English, 0.072 Arabic). Reserve the
   scrollbar's place, and keep the empty shell invisible until app.js fills it (visibility is not a layout shift). */
html { -webkit-text-size-adjust: 100%; scrollbar-gutter: stable; }
main:has(> #head:empty) { visibility: hidden; animation: shellReveal 0s 3s forwards; }
@keyframes shellReveal { to { visibility: visible; } }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.6 system-ui, -apple-system, "Segoe UI", Tahoma, "Noto Sans Arabic", Arial, sans-serif; }
main { max-width: 1280px; margin: 0 auto; padding: 16px; display: grid; gap: 16px; grid-template-columns: minmax(0, 1fr); }
#form, #result, section { min-width: 0; }
@media (min-width: 900px) { main { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); align-items: start; } #head { grid-column: 1 / -1; } }
.brand { display: flex; justify-content: space-between; gap: 12px; align-items: center; font-weight: 700; margin-bottom: 10px; }
.lang { color: var(--accent); font-weight: 600; padding: 8px 4px; }
.tabs { display: flex; gap: 8px; }
.tab { flex: 1; min-height: 46px; border: 1px solid var(--line); background: var(--card); color: var(--text); border-radius: 8px; font: inherit; font-weight: 600; cursor: pointer; }
.tab.on { background: var(--accent); border-color: var(--accent); color: var(--card); }
h1 { font-size: 1.4rem; margin: 0 0 4px; line-height: 1.3; }
h2 { font-size: 1.05rem; margin: 0 0 8px; }
.intro { margin: 0 0 12px; color: var(--muted); }
.card, #result { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 14px; }
.card { margin-bottom: 12px; }
.row-head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 8px; }
.grid { display: grid; gap: 10px; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); }
.with-unit { display: grid; grid-template-columns: minmax(0, 1fr) 76px; gap: 6px; align-items: end; }
.field { display: grid; gap: 4px; margin-bottom: 8px; min-width: 0; }
.with-unit .field, .grid > .field { margin-bottom: 0; }
label { font-size: .9rem; font-weight: 600; }
input, select { width: 100%; min-height: 46px; padding: 8px 10px; font: inherit; color: var(--text); background: var(--bg); border: 1px solid var(--line); border-radius: 8px; }
input { direction: ltr; text-align: start; }
[dir="rtl"] input { text-align: right; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 1px; }
button { font: inherit; cursor: pointer; }
.link { background: none; border: 0; color: var(--err); padding: 8px; min-height: 40px; text-decoration: underline; }
.add { width: 100%; min-height: 46px; background: var(--accent-soft); color: var(--text); border: 1px dashed var(--accent); border-radius: 8px; font-weight: 600; margin-bottom: 12px; }
.options { margin-bottom: 4px; }
#result section { margin-bottom: 18px; }
.report-head { display: none; }
.stats { display: grid; gap: 6px; }
.stat { display: flex; justify-content: space-between; gap: 12px; padding: 8px 10px; border-radius: 8px; background: var(--bg); }
.stat.strong { background: var(--accent-soft); font-weight: 700; font-size: 1.15rem; }
.num { font-variant-numeric: tabular-nums; }
.scroll { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; font-size: .9rem; }
th, td { border: 1px solid var(--line); padding: 6px 8px; text-align: start; white-space: nowrap; }
th { background: var(--bg); }
.steps, ul { margin: 0; padding-inline-start: 22px; }
.steps li { margin-bottom: 8px; }
.steps bdi { display: block; font-weight: 600; overflow-wrap: anywhere; }
.warn { background: var(--warn-bg); color: var(--warn); padding: 10px; border-radius: 8px; margin: 10px 0 0; }
.problem { color: var(--err); font-weight: 600; margin: 0 0 12px; }
.actions { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-bottom: 18px; }
.actions button, .clear, .danger { min-height: 46px; border-radius: 8px; font-weight: 700; padding: 6px 12px; }
.primary { background: var(--accent); color: var(--card); border: 0; }
.secondary, .clear { background: transparent; color: var(--text); border: 1px solid var(--line); }
.danger { background: var(--err); color: var(--card); border: 0; }
.clear { width: 100%; margin-top: 4px; font-weight: 600; }
.clear-confirm { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-top: 4px; }
.clear-confirm span { grid-column: 1 / -1; font-weight: 600; }
.clear-confirm .clear { margin: 0; }
.hint { background: var(--bg); border-radius: 8px; padding: 12px; margin-bottom: 12px; }
.hint p { margin: 0; }
.hint .example { color: var(--muted); margin-top: 6px; }
.stat.strong span:last-child { font-size: 1.5rem; line-height: 1.2; }
.sketch-box { margin: 2px 0 10px; background: var(--bg); border-radius: 8px; }
.sketch { display: block; width: 100%; max-width: 420px; height: auto; margin: 0 auto; }
.face-top { fill: var(--accent-soft); stroke: var(--text); stroke-width: 1; }
.face-left { fill: var(--line); stroke: var(--text); stroke-width: 1; }
.face-right { fill: var(--card); stroke: var(--text); stroke-width: 1; }
.steel { fill: var(--muted); }
.rib { stroke: var(--card); stroke-width: 1.5; }
.dim-line { stroke: var(--accent); stroke-width: 1.5; }
.dim { fill: var(--text); font-size: 12px; font-weight: 600; }
.dim.strong { fill: var(--accent); font-weight: 700; }
.scale-note { color: var(--muted); font-size: .85rem; margin: 8px 0; }
.privacy { color: var(--muted); font-size: .85rem; margin: 10px 0 0; }
@media print {
  :root { color-scheme: light; --bg: #fff; --card: #fff; --text: #000; --muted: #333; --line: #888; --accent-soft: #eee; --warn-bg: #fff; --warn: #000; }
  #head, #form, .actions { display: none !important; }
  main { display: block; padding: 0; max-width: none; }
  #result { border: 0; padding: 0; }
  .report-head { display: flex; flex-direction: column; margin-bottom: 14px; border-bottom: 2px solid #000; padding-bottom: 8px; }
  .scroll { overflow: visible; }
  th, td { white-space: normal; }
  section { break-inside: avoid; }
}