/* ── Bevel Protractor Simulator ──────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --surface:   #161b27;
  --surface2:  #1f2535;
  --border:    #2a3050;
  --accent:    #ffd600;
  --accent-lo: rgba(255,214,0,.22);
  --green:     #3ddc84;
  --red:       #ff5555;
  --gold:      #f5c842;
  --text:      #dde3f0;
  --text-dim:  #6b7a99;
  --font:      'Segoe UI', system-ui, sans-serif;
  --mono:      'Courier New', monospace;
  --radius:    12px;
  /* cell accent colours */
  --msr:  #4fc3f7;   /* blue  — MSR    */
  --vsc:  #81c784;   /* green — VSC    */
  --lc:   #ffb74d;   /* gold  — LC     */
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  min-height: 100vh;
  padding: 20px 16px 36px;
}

#app { max-width: 980px; margin: 0 auto; display: flex; flex-direction: column; gap: 14px; }

/* ── Header ─────────────────────────────────────────────────── */
header { text-align: center; padding: 4px 0; }
header h1 {
  font-size: 1.8rem; font-weight: 700;
  background: linear-gradient(120deg, #ffd600 0%, #fff176 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.subtitle { color: var(--text-dim); font-size: 0.85rem; margin-top: 3px; }

/* ── Controls bar ────────────────────────────────────────────── */
.controls-bar {
  display: flex; flex-wrap: wrap; align-items: center; gap: 14px;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.ctrl-group { display: flex; align-items: center; gap: 8px; }
.ctrl-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-dim); white-space: nowrap; }
.lc-hint { font-size: 0.65rem; opacity: 0.65; text-transform: none; letter-spacing: 0; }
.lc-badge {
  font-size: 0.78rem; font-weight: 700; color: var(--lc);
  background: rgba(255,183,77,.12); border: 1px solid rgba(255,183,77,.3);
  border-radius: 6px; padding: 3px 10px;
}

.pill-tabs { display: flex; background: var(--bg); border-radius: 8px; padding: 3px; gap: 2px; }
.pill {
  padding: 5px 13px; border: none; background: transparent; color: var(--text-dim);
  border-radius: 6px; cursor: pointer; font-size: 0.81rem; transition: background .18s, color .18s, box-shadow .18s;
}
.pill.active { background: var(--accent); color: #1a1a1a; font-weight: 700; box-shadow: 0 0 12px var(--accent-lo); }
.pill:hover:not(.active) { background: var(--surface2); color: var(--text); }

/* ── Canvas card ──────────────────────────────────────────────── */
.canvas-card {
  position: relative;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 10px; cursor: crosshair; overflow-x: clip;
}
.canvas-card:active { cursor: crosshair; }
#main-canvas { display: block; margin: 0 auto; touch-action: none; width: 100%; height: auto; max-width: 923px; }

.drag-hint {
  position: absolute; bottom: 12px; right: 16px;
  font-size: 0.72rem; color: var(--text-dim); pointer-events: none; transition: opacity .4s;
}
.drag-hint.hidden { opacity: 0; }

/* ── Zoom toggle (inside canvas card) ───────────────────────── */
.zoom-toggle {
  position: absolute; top: 12px; right: 14px; z-index: 10;
  background: rgba(13,17,23,0.80); border: 1px solid rgba(255,214,0,0.42);
  color: #ffd600; border-radius: 8px; padding: 5px 13px;
  font-size: 0.78rem; font-weight: 600; cursor: pointer;
  transition: background .18s, box-shadow .18s, border-color .18s;
  -webkit-backdrop-filter: blur(6px); backdrop-filter: blur(6px);
}
.zoom-toggle:hover { background: rgba(30,42,70,0.90); box-shadow: 0 0 12px rgba(255,214,0,.28); }
.zoom-toggle.active { background: rgba(255,214,0,0.15); border-color: var(--accent); color: #fff; }

/* ── Info row (grid layout for measuring instruments) ────────── */
.info-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
}

/* ── Reading cells ──────────────────────────────────────────── */
.reading-cell {
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  background: var(--surface2); border: 1px solid var(--border); border-radius: 10px;
  padding: 12px 8px; text-align: center; position: relative; overflow: hidden;
  transition: filter .35s ease;
}
.reading-cell::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px; border-radius: 10px 10px 0 0;
}

/* Digital reading cell - special styling */
.digital-reading {
  background: #060a0e; border: 2px solid rgba(255,214,0,.25);
  box-shadow: inset 0 0 24px rgba(255,214,0,.04), 0 0 16px rgba(255,214,0,.07);
}
.digital-reading::before { background: var(--accent); }
.digital-reading .rc-label { color: rgba(255,214,0,.5); }
.digital-reading .rc-value {
  font-size: 1.6rem; color: #ffd600;
  text-shadow: 0 0 10px rgba(255,214,0,.55);
}

.rc-label {
  font-size: 0.62rem; font-weight: 700; text-transform: uppercase; letter-spacing: .1em;
  color: var(--text-dim); margin-bottom: 4px;
}
.rc-value {
  font-family: var(--mono); font-size: 1.35rem; font-weight: 700;
  color: var(--text); line-height: 1; margin: 2px 0;
}

/* Cell accent colors */
.reading-cell:nth-child(2)::before { background: var(--msr); }
.reading-cell:nth-child(2) .rc-label { color: var(--msr); }
.reading-cell:nth-child(3)::before { background: var(--vsc); }
.reading-cell:nth-child(3) .rc-label { color: var(--vsc); }
.reading-cell:nth-child(4)::before { background: var(--lc); }
.reading-cell:nth-child(4) .rc-label { color: var(--lc); }

/* Hide values during practice/quiz */
.cells-hidden .rc-value { filter: blur(7px); user-select: none; -webkit-user-select: none; }

/* ── Formula display ─────────────────────────────────────────── */
.tr-formula {
  grid-column: 1 / -1;
  background: var(--surface2); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 16px; display: flex; flex-wrap: wrap; align-items: center; gap: 8px 16px;
  font-family: var(--mono); font-size: 0.88rem; color: var(--text-dim);
  transition: filter .35s ease;
}
.tr-formula .tr-title {
  font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: .06em;
  color: var(--accent);
}
.tr-formula .tr-eq { color: var(--text); font-weight: 700; }
.tr-formula .tr-result {
  font-weight: 700; color: var(--gold); text-shadow: 0 0 8px rgba(245,200,66,.4);
  font-size: 1.05rem;
}
.tr-formula span.f-msr { color: var(--msr); font-weight: 700; }
.tr-formula span.f-vsc { color: var(--vsc); font-weight: 700; }
.tr-formula span.f-lc  { color: var(--lc);  font-weight: 700; }
.formula-hidden { filter: blur(7px); user-select: none; -webkit-user-select: none; }

/* ── Buttons ─────────────────────────────────────────────────── */
.btn {
  padding: 8px 18px; border: none; border-radius: 8px; cursor: pointer;
  font-size: 0.84rem; font-weight: 600; transition: filter .18s, box-shadow .18s, opacity .18s;
}
.btn:disabled { opacity: 0.38; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #1a1a1a; }
.btn-primary:not(:disabled):hover { filter: brightness(1.12); box-shadow: 0 0 12px var(--accent-lo); }
.btn-ghost { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--border); }

/* ── Practice bar ────────────────────────────────────────────── */
.practice-bar {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.pbar-score { font-size: 0.84rem; color: var(--text-dim); margin-left: auto; white-space: nowrap; }
.pbar-score span { color: var(--text); font-weight: 700; }

.feedback { font-size: 0.88rem; font-weight: 600; min-width: 0; }
.feedback.ok  { color: var(--green); }
.feedback.err { color: var(--red); }

/* ── Practice panel ──────────────────────────────────────────── */
.practice-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px;
}
.pp-prompt {
  font-size: 0.9rem; color: var(--text); margin-bottom: 12px; font-weight: 600;
}
.pp-input-row {
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
}
.pp-input {
  width: 80px; padding: 8px 10px; border: 2px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text); font-family: var(--mono); font-size: 1.1rem;
  font-weight: 700; text-align: center; outline: none;
  transition: border-color .18s;
  -moz-appearance: textfield;
}
.pp-input::-webkit-outer-spin-button,
.pp-input::-webkit-inner-spin-button { -webkit-appearance: none; }
.pp-input:focus { border-color: var(--accent); box-shadow: 0 0 8px var(--accent-lo); }
.pp-unit {
  font-size: 0.85rem; font-weight: 700; color: var(--text-dim);
}
.pp-feedback {
  margin-top: 10px; font-size: 0.88rem; font-weight: 600; min-height: 1.4em;
}
.pp-feedback.ok  { color: var(--green); }
.pp-feedback.err { color: var(--red); }

/* ── Quiz bar ────────────────────────────────────────────────── */
.quiz-bar {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.qbar-counter {
  display: flex; align-items: baseline; gap: 3px;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px; padding: 4px 12px;
}
.qbar-q-label { font-size: 0.7rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: .08em; }
.qbar-q-num   { font-family: var(--mono); font-size: 1.3rem; font-weight: 700; color: var(--text); line-height: 1; }
.qbar-q-sep   { font-size: 0.82rem; color: var(--text-dim); }
.qbar-q-total { font-family: var(--mono); font-size: 0.88rem; color: var(--text-dim); }
.qbar-hint    { font-size: 0.78rem; color: var(--text-dim); }
.quiz-feedback { font-size: 0.88rem; font-weight: 600; }
.quiz-feedback.ok  { color: var(--green); }
.quiz-feedback.err { color: var(--red); }

/* ── Question panel (quiz mode) ──────────────────────────────── */
.question-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px;
}

/* ── Answer grid (quiz multiple choice) ──────────────────────── */
.answer-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-top: 12px;
}
.answer-btn {
  padding: 12px 16px; border: 2px solid var(--border); border-radius: 10px;
  background: var(--surface2); color: var(--text); font-family: var(--mono);
  font-size: 1rem; font-weight: 700; cursor: pointer; text-align: center;
  transition: border-color .18s, background .18s, box-shadow .18s;
}
.answer-btn:hover { border-color: var(--accent); background: rgba(255,214,0,.08); }
.answer-btn.correct { border-color: var(--green); background: rgba(61,220,132,.12); color: var(--green); }
.answer-btn.wrong   { border-color: var(--red);   background: rgba(255,85,85,.12);  color: var(--red); }
.answer-btn:disabled { cursor: not-allowed; opacity: 0.7; }

/* ── Quiz result panel ───────────────────────────────────────── */
.quiz-result {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px; display: flex; flex-direction: column; gap: 14px;
}
.qr-header { display: flex; align-items: flex-start; justify-content: space-between; }
.qr-title-wrap { display: flex; flex-direction: column; gap: 5px; }
.qr-title  { font-size: 1.1rem; font-weight: 700; color: var(--text); }
.qr-stars  { font-size: 1.2rem; letter-spacing: 3px; }
.qr-score-wrap { text-align: right; }
.qr-score {
  font-family: var(--mono); font-size: 2.2rem; font-weight: 700; line-height: 1;
  text-shadow: 0 0 14px currentColor;
}
.qr-score.perfect { color: var(--gold); }
.qr-score.good    { color: var(--green); }
.qr-score.poor    { color: var(--red); }
.qr-verdict { font-size: 0.72rem; color: var(--text-dim); margin-top: 3px; }

.qr-rows { display: flex; flex-direction: column; gap: 7px; }
.qr-row {
  display: grid; grid-template-columns: 30px 1fr 1fr 26px;
  align-items: center; gap: 10px;
  background: var(--surface2); border: 1px solid var(--border);
  border-left-width: 3px; border-radius: 8px; padding: 9px 12px;
}
.qr-row.ok  { border-left-color: var(--green); }
.qr-row.err { border-left-color: var(--red); }
.qr-qnum    { font-size: 0.72rem; font-weight: 700; color: var(--accent); }
.qr-correct, .qr-given { font-size: 0.78rem; color: var(--text-dim); }
.qr-correct strong, .qr-given strong { color: var(--text); font-family: var(--mono); }
.qr-mark { text-align: right; font-size: 1rem; font-weight: 700; }
.qr-row.ok  .qr-mark { color: var(--green); }
.qr-row.err .qr-mark { color: var(--red); }

/* ── SEO article — inherits from shared/site.css ─────────────── */

/* ── Responsive: 768px ───────────────────────────────────────── */
@media (max-width: 768px) {
  .info-row {
    grid-template-columns: repeat(2, 1fr);
  }
  .tr-formula {
    grid-column: 1 / -1;
  }
}

/* ── Responsive: 500px ───────────────────────────────────────── */
@media (max-width: 500px) {
  .info-row {
    grid-template-columns: 1fr;
  }
  header h1 { font-size: 1.35rem; }
  .subtitle  { font-size: 0.78rem; }
  .rc-value  { font-size: 1.1rem; }
  .digital-reading .rc-value { font-size: 1.3rem; }
  .tr-formula { font-size: 0.78rem; }
  .pp-input { width: 65px; font-size: 0.95rem; }
  .practice-bar { gap: 8px; padding: 10px 12px; }
  .quiz-bar { gap: 8px; padding: 10px 12px; }
}