/* Extends /lab/9-klass/style.css: shared palette, typography, topbar and buttons. */
.rd-page { color-scheme: dark; }
.rd-page * { box-sizing: border-box; }
.rd-app { max-width:1240px; }
.rd-crumbs { display:flex;flex-wrap:wrap;gap:8px;color:var(--muted);font-size:14px;padding-top:14px; }
.rd-crumbs a { text-decoration:none; }
.rd-intro { padding:28px 0 24px; }
.rd-intro .eyebrow { margin:0 0 12px;font-size:12px; }
.rd-intro h1 { font-size:clamp(30px,4.1vw,52px);letter-spacing:-.035em;line-height:1.13;margin:0 0 14px; }
.rd-lead { color:#b3c3d7;max-width:850px;font-size:18px;margin:0; }
.rd-lab { background:linear-gradient(140deg,#0d1a2d,#081220);border:1px solid var(--line);border-radius:24px;padding:24px; }
.rd-lab-head,.rd-chart-head { display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap; }
.rd-lab h2 { font-size:23px;margin:4px 0; }
.rd-kicker { font-size:12px;font-weight:800;letter-spacing:.12em;color:var(--accent); }
.rd-status { padding:6px 12px;border:1px solid #344a64;border-radius:99px;color:#bdd0e4;font-size:14px; }
.rd-run-buttons { display:flex;flex-wrap:wrap;gap:8px; }
.rd-instruction { color:var(--muted);margin:8px 0 22px; }
.rd-workspace { display:grid;grid-template-columns:245px minmax(0,1fr);gap:24px; }
.rd-controls { padding:18px;background:#081321;border:1px solid var(--line);border-radius:16px; }
.rd-controls label { display:block;font-size:14px;font-weight:700;margin:0 0 7px; }
.rd-controls select { display:block;width:100%;min-height:44px;padding:9px 12px;border-radius:9px;background:#101f33;color:var(--text);border:1px solid #35475f;margin-bottom:17px;font:inherit; }
.rd-controls #half-life { margin-bottom:5px; }
.rd-help { color:var(--muted);font-size:14px;line-height:1.5; }
.rd-controls .rd-help { margin:0 0 16px; }
.rd-buttons { display:grid;gap:8px;margin:20px 0 15px; }
.rd-page .button { cursor:pointer;font-size:14px;min-height:44px;padding:10px 13px;border-radius:10px;line-height:1.4; }
.rd-page button:disabled,.rd-page select:disabled { opacity:.45;cursor:default;transform:none; }
.rd-page :focus-visible { outline:3px solid #ffcf7f;outline-offset:4px; }
.rd-observation { min-width:0; }
.rd-field-heading { display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap;font-size:14px;color:var(--muted);margin:0 0 10px; }
.rd-field-heading span:first-child { color:var(--text);font-weight:700; }
#nuclei { width:100%;height:310px;display:block;border-radius:14px;background:radial-gradient(ellipse at center,rgba(83,212,255,.055),transparent 75%),#050d18;border:1px solid var(--line); }
.rd-legend { display:flex;gap:14px;flex-wrap:wrap;font-size:14px;color:#b8c8db;margin:12px 0; }
.rd-legend span { display:inline-flex;align-items:center;gap:7px; }
.rd-legend i { display:inline-block;flex-shrink:0; }
.rd-dot-alive { width:9px;height:9px;border-radius:50%;background:#53d4ff; }
.rd-dot-decayed { width:9px;height:9px;border:1px solid #71839b;border-radius:50%; }
.rd-metrics { display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1px;border:1px solid var(--line);background:var(--line);border-radius:12px;overflow:hidden;margin:16px 0 0; }
.rd-metrics div { padding:12px;background:#0c192b; }
.rd-metrics dt { color:var(--muted);font-size:13px; }
.rd-metrics dd { margin:4px 0 0;font-size:26px;font-weight:700;font-variant-numeric:tabular-nums;line-height:1.2; }
.rd-metrics div:nth-child(2) dd { color:var(--accent); }
.rd-timeline { position:relative;margin:28px 0 0;padding-top:12px; }
.rd-timeline::before,.rd-timeline-fill { position:absolute;top:0;height:3px;left:0;background:#243349;border-radius:4px; }
.rd-timeline::before { content:'';width:100%; }
.rd-timeline-fill { background:var(--accent);width:0; }
.rd-timeline ol { list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:5px; }
.rd-timeline li { color:var(--muted);font-size:14px;text-align:center; }
.rd-timeline b,.rd-timeline span { display:block; }
.rd-timeline .passed b::before { content:'✓ '; }
.rd-timeline .passed { color:var(--accent); }
.rd-center { text-align:center; }
.rd-chart-panel { padding-top:22px;border-top:1px solid var(--line);margin-top:22px; }
.rd-chart-panel h3 { margin:0;font-size:18px; }
.rd-chart-panel .rd-help { margin:5px 0; }
.rd-line-theory { width:23px;border-top:2px dashed #b39bff; }
.rd-line-experiment { width:23px;border-top:3px solid #53d4ff; }
#chart { display:block;width:100%;height:250px; }
.rd-callout { background:rgba(83,212,255,.06);border:1px solid rgba(83,212,255,.25);border-left:3px solid var(--accent);padding:18px 20px;border-radius:12px;margin-top:22px; }
.rd-callout h3,.rd-callout h4 { margin:0 0 8px; }
.rd-callout p { margin:8px 0;color:#b8c8db; }
.rd-callout strong { color:var(--text); }
.rd-history { margin-top:24px; }
.rd-history h3 { margin-bottom:6px; }
.rd-history ol { padding-left:25px;color:#b8c8db; }
.rd-history li { margin:8px 0; }
.rd-section { margin-top:48px; }
.rd-section h2 { font-size:clamp(24px,3vw,32px);letter-spacing:-.025em;margin:8px 0 12px;line-height:1.2; }
.rd-section > p { color:#b8c8db;max-width:900px; }
.rd-isotopes { display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:12px;margin-top:24px; }
.rd-isotopes button { text-align:left;cursor:pointer;color:var(--text);background:#0b1829;border:1px solid #2c3c52;border-radius:15px;padding:18px 14px;font:inherit;min-width:0; }
.rd-isotopes b,.rd-isotopes span,.rd-isotopes small { display:block; }
.rd-isotopes b { font-size:30px;color:var(--accent);margin-bottom:12px; }
.rd-isotopes small { color:var(--muted);font-size:14px;margin-top:6px; }
.rd-isotopes button[aria-pressed=true] { border-color:var(--accent);background:#132c40; }
.rd-isotopes button[aria-pressed=true] span::before { content:'✓ '; }
.rd-page details { border:1px solid var(--line);padding:16px 20px;border-radius:12px;margin-top:20px; }
.rd-page summary { cursor:pointer;min-height:28px;font-weight:700; }
.rd-page details a { color:var(--accent); }
.rd-page details li { margin:10px 0; }
.rd-quiz { padding:26px;border:1px solid var(--line);border-radius:22px;background:linear-gradient(120deg,#101d33,#09121f); }
.rd-answers { display:flex;flex-wrap:wrap;gap:12px;margin:22px 0; }
.rd-answers button { flex:1;min-width:70px;min-height:52px;color:var(--text);background:#14263e;border:1px solid #455975;border-radius:10px;cursor:pointer;font:700 20px Arial,sans-serif; }
.rd-answers button[data-result=correct] { border-color:#59d7a4; }
.rd-answers button[data-result=wrong] { border-color:#ffb45e; }
#quiz-feedback { margin-bottom:20px; }
.rd-chain { font-size:clamp(18px,3vw,26px);font-weight:700;color:var(--accent); }
.rd-learning-grid { display:grid;grid-template-columns:1fr 1fr;gap:32px; }
.rd-learning-grid h2 { font-size:21px;margin-top:15px; }
.rd-learning p { color:#b8c8db; }
.rd-equation { font-size:clamp(19px,3vw,28px); }
.rd-back { display:inline-block;color:var(--accent);margin-top:35px;font-weight:700;padding:10px 0; }
.rd-page .rd-footer { display:block;max-width:1240px;padding:24px 28px;margin:auto;border-top:1px solid var(--line);color:var(--muted);font-size:14px; }
.rd-sr,.rd-skip { position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%); }
.rd-skip:focus { position:relative;display:block;width:auto;height:auto;clip-path:none;padding:15px; }
.rd-page [hidden] { display:none!important; }
@media(max-width:900px) { .rd-workspace { grid-template-columns:210px minmax(0,1fr);gap:16px; }.rd-isotopes { grid-template-columns:repeat(3,minmax(0,1fr)); } }
@media(max-width:700px) { .rd-page .topbar { padding:18px 16px;flex-wrap:wrap;gap:14px; }.rd-page .topbar nav { flex-wrap:wrap;gap:16px; }.rd-page main { padding:0 14px 40px; }.rd-lab { padding:16px;border-radius:18px; }.rd-workspace { grid-template-columns:1fr; }.rd-controls { display:grid;grid-template-columns:1fr 1fr;gap:8px 12px;padding:14px; }.rd-controls label { align-self:center; }.rd-controls select { margin:0; }.rd-controls .rd-help,.rd-buttons { grid-column:1/-1;margin:4px 0; }.rd-buttons { grid-template-columns:1fr 1fr; }.rd-metrics dt { font-size:12px; }.rd-metrics dd { font-size:23px; }.rd-metrics div { padding:10px 8px; }.rd-timeline li { font-size:12px; }.rd-timeline .passed b::before { content:''; }.rd-timeline .passed b { text-decoration:underline;text-underline-offset:4px; }.rd-learning-grid { grid-template-columns:1fr;gap:10px; }.rd-isotopes { grid-template-columns:repeat(2,minmax(0,1fr)); }.rd-quiz { padding:20px 16px; }.rd-callout { padding:14px; }.rd-section { margin-top:35px; }.rd-lead { font-size:16px; } }
@media(prefers-reduced-motion:reduce) { .rd-page { scroll-behavior:auto; }.rd-page * { animation:none!important;transition:none!important; }.rd-page .button:hover { transform:none; } }


.rd-course-nav { display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:42px; }
.rd-course-nav a { min-height:96px;padding:17px 18px;border:1px solid var(--line);border-radius:16px;background:#0b1829;color:var(--text);text-decoration:none;display:flex;flex-direction:column;justify-content:center;transition:.18s ease; }
.rd-course-nav a:hover { border-color:rgba(83,212,255,.35);background:#102238;transform:translateY(-2px); }
.rd-course-nav small { color:var(--muted);font-size:9px;letter-spacing:.11em;margin-bottom:6px; }
.rd-course-nav strong { font-size:16px;line-height:1.35; }
@media(max-width:700px) { .rd-course-nav { grid-template-columns:1fr; } }
@media(prefers-reduced-motion:reduce) { .rd-course-nav a:hover { transform:none; } }