/* HMT Study — dark, readable, phone-first theme. */
:root {
  --bg: #12151c;
  --card: #1b202b;
  --card2: #232a38;
  --line: #33405a;
  --text: #eef1f6;
  --muted: #a9b4c7;
  --accent: #f5b301;
  --green: #3ecf7a;
  --red: #e05d5d;
  --blue: #5aa9ff;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  line-height: 1.55;
  font-size: 17px;
}
a { color: var(--blue); }
.hidden { display: none !important; }
.wrap { max-width: 760px; margin: 0 auto; padding: 12px 14px 40px; }
.topbar {
  display: flex; justify-content: space-between; align-items: center; gap: 10px;
  max-width: 760px; margin: 0 auto; padding: 14px;
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; gap: 12px; align-items: center; }
.brand-mark {
  background: var(--accent); color: #12151c; font-weight: 800; font-size: 22px;
  padding: 8px 10px; border-radius: 8px; letter-spacing: 1px;
}
.brand h1 { margin: 0; font-size: 24px; line-height: 1.1; }
.subtitle { margin: 2px 0 0; color: var(--muted); font-size: 13px; }
.member-box { text-align: right; font-size: 14px; color: var(--muted); }
.member-box button { margin-top: 4px; }
.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: 12px; padding: 16px; margin: 14px 0;
}
.center { text-align: center; }
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; margin: 14px 0; }
.btn, .tab-btn, .track-btn {
  font-size: 16px; padding: 11px 16px; border-radius: 9px; cursor: pointer;
  border: 1px solid var(--line); background: var(--card2); color: var(--text);
}
.btn.primary { background: var(--accent); color: #12151c; border-color: var(--accent); font-weight: 700; }
.btn.small { padding: 7px 12px; font-size: 14px; }
.btn:disabled { opacity: 0.55; cursor: default; }
.small { color: var(--muted); font-size: 14px; }
.dont-box {
  background: #2b2410; border: 1px solid var(--accent); border-radius: 12px;
  padding: 14px 16px; margin: 14px 0; font-size: 16px;
}
.track-nav { display: flex; gap: 8px; flex-wrap: wrap; margin: 14px 0 0; }
.track-btn.active, .tab-btn.active { background: var(--accent); color: #12151c; border-color: var(--accent); font-weight: 700; }
.tab-nav { display: flex; gap: 8px; flex-wrap: wrap; margin: 4px 0 0; }
.progress-card p { margin: 6px 0; }
.progress-card .bar { height: 10px; background: var(--card2); border-radius: 6px; overflow: hidden; }
.progress-card .bar > div { height: 100%; background: var(--green); }
/* Sticky header progress bar: stays visible while scrolling lessons. */
#progressBar { position: sticky; top: 0; z-index: 60; padding: 10px 16px; }
.sticky-progress .sp-row { display: flex; gap: 10px; align-items: baseline; flex-wrap: wrap; }
.sticky-progress .sp-track { font-weight: 700; }
.sticky-progress .sp-count { color: var(--muted); font-size: 14px; }
.sticky-progress .sp-pct { margin-left: auto; font-weight: 700; font-size: 15px; }
.sticky-progress .bar { height: 8px; background: var(--card2); border-radius: 6px; overflow: hidden; margin-top: 8px; }
.sticky-progress .bar > div { height: 100%; background: var(--green); }
/* Track-screen progress bar (same green bar, inside the content card flow). */
.content .bar { height: 10px; background: var(--card2); border-radius: 6px; overflow: hidden; margin: 10px 0; }
.content .bar > div { height: 100%; background: var(--green); }
.lesson { border-top: 1px solid var(--line); padding: 14px 0; }
.lesson:first-child { border-top: 0; padding-top: 0; }
.lesson h3 { margin: 0 0 6px; }
.lesson p { margin: 8px 0; }
.tag { display: inline-block; background: var(--card2); border: 1px solid var(--line); color: var(--muted); border-radius: 20px; padding: 2px 10px; font-size: 13px; margin-right: 6px; }
.lesson-page h2 { margin: 8px 0; }
.lesson-nav { margin: 10px 0; }
.lesson-nav .btn { text-decoration: none; text-align: center; }
.section-box { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 16px; margin: 14px 0; }
.dots { display: flex; gap: 6px; align-items: center; }
.dot { width: 10px; height: 10px; border-radius: 50%; background: var(--card2); border: 1px solid var(--line); }
.dot.on { background: var(--accent); border-color: var(--accent); }
.pop-q { border-top: 1px solid var(--line); padding: 14px 0; }
.pop-q:first-child { border-top: 0; }
.pop-why .why { margin: 10px 0 0; }
.quiz-q { font-size: 19px; font-weight: 700; }
.opt-btn { display: block; width: 100%; text-align: left; margin: 8px 0; }
.opt-btn.correct { background: #123d26; border-color: var(--green); }
.opt-btn.wrong { background: #3d1414; border-color: var(--red); }
.why { background: var(--card2); border-left: 4px solid var(--accent); padding: 12px 14px; border-radius: 0 8px 8px 0; margin: 14px 0; }
.why strong { color: var(--accent); }
.walk { border-top: 1px solid var(--line); padding: 16px 0; }
.walk:first-child { border-top: 0; }
.step-box { background: var(--card2); border: 1px solid var(--line); border-radius: 10px; padding: 14px; margin: 10px 0; }
.sim { background: var(--card2); border: 1px solid var(--line); border-radius: 12px; padding: 14px; margin: 12px 0; }
.sim svg { width: 100%; height: auto; display: block; background: #0e1420; border-radius: 8px; }
.sim label { display: block; margin: 12px 0 2px; color: var(--muted); font-size: 14px; }
.sim input[type="range"] { width: 100%; }
.readout { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }
.readout span { background: #0e1420; border: 1px solid var(--line); border-radius: 8px; padding: 6px 10px; font-size: 14px; }
.readout .warn { border-color: var(--red); color: var(--red); }
.readout .good { border-color: var(--green); color: var(--green); }
.spin { transform-origin: center; transform-box: fill-box; animation: spin 1.2s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.piston { animation: piston 2.4s ease-in-out infinite; }
@keyframes piston { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(26px); } }
.gauge-fill { transition: width 0.3s ease; }
.flow-dot { animation: flowmove 1.1s linear infinite; }
@keyframes flowmove { from { offset-distance: 0%; } to { offset-distance: 100%; } }
.disclaimer { color: var(--muted); font-size: 13px; border-top: 1px solid var(--line); margin-top: 24px; padding-top: 14px; }
@media (max-width: 480px) {
  body { font-size: 16px; }
  .subtitle { display: none; }
  .btn, .tab-btn, .track-btn { padding: 12px 13px; }
}