/* ═══════════════════════════════════════════════════════════
   Fatigue Testing Virtual Lab — style.css
   Accent: #5e35b1 (deep indigo-purple)
   ═══════════════════════════════════════════════════════════ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --surface:   #161b27;
  --surface2:  #1f2535;
  --border:    #2a3050;
  --accent:    #5e35b1;
  --accent-lo: rgba(94,53,177,.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;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  min-height: 100vh;
  padding: 0 16px;
}

#app {
  max-width: 1400px;
  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, var(--accent) 0%, #b39ddb 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.subtitle { color: var(--text-dim); font-size: .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: .72rem; text-transform: uppercase; letter-spacing: .06em;
  color: var(--text-dim); white-space: nowrap;
}

/* ── Pill tabs ── */
.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: .81rem;
  transition: background .18s, color .18s, box-shadow .18s;
}
.pill.active {
  background: var(--accent); color: #fff; box-shadow: 0 0 12px var(--accent-lo);
}
.pill:hover:not(.active) { background: var(--surface2); color: var(--text); }

/* ── Buttons ── */
.btn {
  padding: 8px 18px; border: none; border-radius: 8px; cursor: pointer;
  font-size: .84rem; font-weight: 600;
  transition: filter .18s, box-shadow .18s, opacity .18s;
}
.btn:disabled { opacity: .38; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #fff; }
.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); }
.btn-danger { background: var(--red); color: #fff; }

/* ── Lab procedure steps ── */
.lab-steps {
  display: flex; gap: 6px; flex-wrap: wrap; align-items: center;
  padding: 10px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  font-size: .76rem;
}
.lab-step {
  display: flex; align-items: center; gap: 4px; color: var(--text-dim);
  transition: color .2s;
}
.lab-step.active { color: var(--accent); font-weight: 700; }
.lab-step.done   { color: var(--green); }
.lab-step-num {
  width: 18px; height: 18px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: .62rem; font-weight: 700;
  background: var(--surface2); border: 1px solid var(--border);
}
.lab-step.active .lab-step-num { background: var(--accent); color: #fff; border-color: var(--accent); }
.lab-step.done   .lab-step-num { background: var(--green); color: #0d1117; border-color: var(--green); }
.lab-step-sep { color: var(--border); font-size: .6rem; }

/* ── Canvas row ── */
.canvas-row {
  display: flex; gap: 14px;
}
.canvas-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 10px;
  overflow-x: clip;
}
.canvas-card canvas {
  display: block; width: 100%; height: auto; touch-action: none;
}
.canvas-card-machine { flex: 0 0 580px; }
.canvas-card-graph   { flex: 1 1 0; min-width: 0; }

/* ── Graph badges ── */
.graph-badges {
  display: flex; gap: 8px; flex-wrap: wrap; margin-top: 8px;
}
.graph-badge {
  display: flex; align-items: center; gap: 5px;
  padding: 4px 10px;
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  font-size: .72rem; color: var(--text-dim);
}
.graph-badge-val {
  font-family: var(--mono); font-weight: 700; color: var(--text); font-size: .78rem;
}

/* ── Controls panel ── */
.sim-controls {
  display: flex; flex-wrap: wrap; gap: 14px; align-items: center;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.mat-tabs {
  display: flex; gap: 4px; flex-wrap: wrap;
}
.mat-pill {
  padding: 4px 10px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--surface2); color: var(--text-dim); cursor: pointer;
  font-size: .74rem; transition: all .18s;
}
.mat-pill.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.mat-pill:hover:not(.active) { border-color: var(--accent); color: var(--text); }

.slider-group {
  display: flex; flex-direction: column; gap: 2px; min-width: 120px;
}
.slider-group label {
  font-size: .68rem; text-transform: uppercase; letter-spacing: .05em; color: var(--text-dim);
}
.slider-group input[type="range"] {
  -webkit-appearance: none; appearance: none; width: 100%; height: 4px;
  background: var(--border); border-radius: 2px; outline: none;
}
.slider-group input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none; width: 14px; height: 14px;
  background: var(--accent); border-radius: 50%; cursor: pointer;
  border: 2px solid #fff;
}
.slider-val {
  font-family: var(--mono); font-size: .74rem; color: var(--text); text-align: right;
}

.action-btns { display: flex; gap: 8px; margin-left: auto; }

/* ── Readout grid ── */
.readout-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.readout-card {
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 12px; text-align: center;
}
.readout-label { font-size: .66rem; text-transform: uppercase; letter-spacing: .04em; color: var(--text-dim); margin-bottom: 4px; }
.readout-value { font-family: var(--mono); font-size: 1.1rem; font-weight: 700; color: var(--accent); }
.readout-unit  { font-size: .68rem; color: var(--text-dim); margin-top: 2px; }

/* ── Explore mode ── */
.explore-wrapper {}
.explore-cats {
  display: flex; gap: 4px; flex-wrap: wrap; margin-bottom: 10px;
}
.explore-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(155px, 1fr));
  gap: 8px; margin-bottom: 14px;
}
.explore-btn {
  padding: 8px 10px; background: var(--surface2); border: 1px solid var(--border);
  border-radius: 8px; color: var(--text-dim); cursor: pointer; font-size: .78rem;
  text-align: left; transition: all .18s;
}
.explore-btn.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.explore-btn:hover:not(.active) { border-color: var(--accent); color: var(--text); }
.explore-info {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 20px; margin-bottom: 14px;
}
.explore-info h3 { font-size: 1rem; color: var(--accent); margin-bottom: 6px; }
.explore-info p  { font-size: .84rem; color: var(--text-dim); line-height: 1.55; }
.explore-info .formula-box {
  margin-top: 10px; padding: 10px 14px;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  font-family: var(--mono); font-size: .82rem; color: var(--accent);
}
.explore-info .example-box {
  margin-top: 10px; padding: 10px 14px;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  font-size: .8rem; color: var(--text-dim); line-height: 1.5;
}
.explore-info .example-box strong { color: var(--text); }
.explore-canvas-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 10px;
  overflow-x: clip;
}
.explore-canvas-card canvas { display: block; width: 100%; height: auto; touch-action: none; }

/* ── Practice mode ── */
.practice-wrapper {}
.practice-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 22px;
}
.practice-prompt { font-size: .92rem; line-height: 1.5; margin-bottom: 14px; }
.practice-input-row { display: flex; gap: 8px; align-items: center; margin-bottom: 10px; }
.practice-input-row input {
  width: 120px; padding: 6px 10px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--bg); color: var(--text); font-family: var(--mono); font-size: .88rem;
}
.practice-input-row .unit { font-size: .78rem; color: var(--text-dim); }
.practice-feedback { font-size: .86rem; font-weight: 600; margin-bottom: 8px; min-height: 1.2em; }
.practice-feedback.ok  { color: var(--green); }
.practice-feedback.err { color: var(--red); }
.practice-solution {
  display: none; margin-top: 10px; padding: 12px 14px;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  font-size: .82rem; line-height: 1.6; color: var(--text-dim);
}
.practice-solution strong { color: var(--text); }
.practice-btns { display: flex; gap: 8px; margin-top: 12px; }
.practice-score { font-size: .82rem; color: var(--text-dim); margin-left: auto; align-self: center; }
.practice-score span { color: var(--text); font-weight: 700; }

/* ── Quiz mode ── */
.quiz-wrapper {}
.quiz-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 22px;
}
.quiz-counter { font-size: .74rem; color: var(--text-dim); margin-bottom: 8px; }
.quiz-prompt { font-size: .92rem; line-height: 1.5; margin-bottom: 14px; }
.quiz-options { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-bottom: 12px; }
.quiz-opt {
  padding: 10px 14px; background: var(--surface2); border: 1px solid var(--border);
  border-radius: 8px; cursor: pointer; font-size: .82rem; color: var(--text);
  transition: all .18s; text-align: left;
}
.quiz-opt:hover { border-color: var(--accent); }
.quiz-opt.correct { background: rgba(61,220,132,.15); border-color: var(--green); color: var(--green); }
.quiz-opt.wrong   { background: rgba(255,85,85,.15); border-color: var(--red); color: var(--red); }
.quiz-opt.disabled { pointer-events: none; opacity: .6; }
.quiz-num-row { display: flex; gap: 8px; align-items: center; margin-bottom: 12px; }
.quiz-num-row input {
  width: 120px; padding: 6px 10px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--bg); color: var(--text); font-family: var(--mono); font-size: .88rem;
}
.quiz-feedback { font-size: .86rem; font-weight: 600; min-height: 1.2em; margin-bottom: 8px; }
.quiz-feedback.ok  { color: var(--green); }
.quiz-feedback.err { color: var(--red); }
.quiz-btns { display: flex; gap: 8px; }

/* Quiz result */
.quiz-result {
  display: none;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px;
}
.qr-title { font-size: 1rem; font-weight: 700; margin-bottom: 4px; }
.qr-stars { font-size: 1.4rem; margin-bottom: 6px; }
.qr-score { font-size: .92rem; font-weight: 700; margin-bottom: 12px; }
.qr-score.perfect { color: var(--gold); }
.qr-score.good    { color: var(--green); }
.qr-score.poor    { color: var(--red); }
.qr-table { width: 100%; border-collapse: collapse; font-size: .8rem; margin-bottom: 14px; }
.qr-table th { text-align: left; padding: 6px 8px; border-bottom: 1px solid var(--border); color: var(--text-dim); }
.qr-table td { padding: 6px 8px; border-bottom: 1px solid var(--border); }
.qr-row.ok  { border-left: 3px solid var(--green); }
.qr-row.err { border-left: 3px solid var(--red); }

/* ── SEO article ── */
.seo-article {
  margin-top: 20px; padding: 24px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  line-height: 1.65; color: var(--text-dim); font-size: .88rem;
}
.seo-article h2 { font-size: 1.2rem; color: var(--text); margin-bottom: 10px; }
.seo-article h3 { font-size: 1rem; color: var(--text); margin: 16px 0 6px; }
.seo-article p  { margin-bottom: 10px; }

/* ── Responsive ── */
@media (max-width: 1200px) {
  .canvas-row { flex-direction: column; }
  .canvas-card-machine { flex: none; }
}
@media (max-width: 768px) {
  .readout-grid { grid-template-columns: 1fr 1fr; }
  .sim-controls { gap: 10px; }
  .quiz-options { grid-template-columns: 1fr; }
}
@media (max-width: 500px) {
  header h1 { font-size: 1.4rem; }
  .subtitle { font-size: .78rem; }
  .readout-grid { grid-template-columns: 1fr; }
  .controls-bar { padding: 10px 12px; gap: 8px; }
  .pill { padding: 5px 10px; font-size: .76rem; }
  .sim-controls { padding: 10px 12px; }
  .action-btns { margin-left: 0; width: 100%; }
  .action-btns .btn { flex: 1; }
}