/* ============================================================
   Periodic Bubbles - sub-page styles (element, learn, about, contact)
   Loaded after app.css. Dark theme, reading-first.
   ============================================================ */
body.subpage{display:block;min-height:100dvh}
.sub-topbar{justify-content:flex-start;gap:14px}
.sub-topbar .brand{display:inline-flex;align-items:center;gap:8px;color:var(--txt);text-decoration:none;font-size:16px}
.sub-topbar .brand-dot{width:12px;height:12px;border-radius:50%;background:radial-gradient(circle at 35% 30%,#ffe082,var(--accent));box-shadow:0 0 10px rgba(255,193,7,.45)}
.sub-topbar .sectnav{margin-left:auto}
@media(max-width:700px){.sub-topbar .brand b{font-size:15px}}

.wrap{max-width:800px;margin:0 auto;padding:22px 16px 60px}
.wrap.wide{max-width:1060px}
.crumbs{font-size:12px;color:var(--muted);display:flex;gap:6px;flex-wrap:wrap;align-items:center;margin-bottom:14px}
.crumbs a{color:var(--muted);text-decoration:none}
.crumbs a:hover{color:var(--txt)}
.crumbs i{font-size:9px}

/* ---- long-form typography ---- */
.prose{font-size:16px;line-height:1.75;color:#d5dced}
.prose h1{font-size:30px;line-height:1.2;margin:6px 0 10px;color:var(--txt);letter-spacing:-.2px}
.prose h2{font-size:21px;line-height:1.3;margin:36px 0 12px;color:var(--txt);padding-top:6px}
.prose h3{font-size:16.5px;margin:26px 0 8px;color:var(--txt)}
.prose p{margin:0 0 16px}
.prose ul,.prose ol{padding-left:24px;margin:0 0 16px}
.prose li{margin-bottom:6px}
.prose a{color:#8fc6de;text-decoration:underline;text-decoration-color:rgba(143,198,222,.4);text-underline-offset:2px}
.prose a:hover{color:var(--accent)}
.prose strong{color:var(--txt)}
.prose table{width:100%;border-collapse:collapse;font-size:14px;margin:0 0 20px;background:var(--panel);border:1px solid var(--line);border-radius:6px;overflow:hidden}
.prose th,.prose td{padding:9px 12px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top;white-space:normal}
.prose th{background:var(--panel-2);color:var(--muted);font-size:11.5px;text-transform:uppercase;letter-spacing:.5px}
.prose tr:last-child td{border-bottom:none}
.tbl-scroll{overflow-x:auto;margin:0 0 20px}
.tbl-scroll table{margin:0}
.lede{font-size:18px;line-height:1.6;color:#b9c3d6;font-weight:600;margin:0 0 20px}
.small{font-size:12.5px;color:var(--muted)}

/* ---- element page ---- */
.el-hero{display:flex;gap:18px;align-items:center;margin:10px 0 14px}
.el-sym{width:88px;height:88px;border-radius:12px;flex:none;display:flex;flex-direction:column;align-items:center;justify-content:center;color:#fff;font-weight:800;font-size:34px;line-height:1;box-shadow:inset 0 0 0 2px rgba(255,255,255,.22),0 10px 30px rgba(0,0,0,.4)}
.el-sym small{font-size:11px;font-weight:600;opacity:.85;margin-top:4px}
.el-hero h1{margin:0 0 6px;font-size:30px;line-height:1.15}
.el-hero h1 span{color:var(--muted);font-weight:600;font-size:18px}
.chips{display:flex;gap:6px;flex-wrap:wrap}
.chips .chip{padding:3px 10px;font-size:11.5px}
.cta{display:flex;gap:8px;margin:18px 0;flex-wrap:wrap}
.cta .ctl{text-decoration:none;display:inline-flex;align-items:center;gap:6px;padding:9px 14px;font-weight:600}
.el-grid{display:grid;gap:18px;margin:22px 0}
@media(min-width:760px){.el-grid{grid-template-columns:300px 1fr;align-items:start}}
.el-grid figure{margin:0}
.el-grid figure img{width:100%;height:auto;aspect-ratio:1/1;object-fit:contain;border-radius:8px;border:1px solid var(--line);background:#fff}
.el-grid figcaption{font-size:11px;color:var(--muted);margin-top:6px;line-height:1.5}
.el-grid .facts{grid-template-columns:repeat(auto-fill,minmax(140px,1fr))}
.prose h2.kicker{font-size:11px;text-transform:uppercase;letter-spacing:.8px;color:var(--muted);margin:0 0 8px;padding:0}

.dyk{list-style:none;padding:0;margin:0 0 20px;display:grid;gap:8px}
.dyk li{background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:11px 14px 11px 40px;position:relative;font-size:14.5px;line-height:1.55}
.dyk li::before{content:'';position:absolute;left:14px;top:15px;width:12px;height:12px;border-radius:50%;background:radial-gradient(circle at 35% 30%,#ffe082,var(--accent));box-shadow:0 0 8px rgba(255,193,7,.4)}

.neigh{display:flex;gap:8px;flex-wrap:wrap;margin:0 0 20px}
.neigh a{display:inline-flex;align-items:center;gap:8px;background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:6px 10px 6px 6px;color:var(--txt);text-decoration:none;font-size:13px}
.neigh a:hover{border-color:var(--accent)}
.neigh .bsym{width:30px;height:30px;border-radius:5px;display:inline-flex;align-items:center;justify-content:center;font-weight:800;font-size:12px;color:#fff}
.neigh .bnum{color:var(--muted);font-size:10.5px;margin-left:2px}
.prevnext{display:flex;justify-content:space-between;gap:10px;margin:26px 0}
.prevnext a{text-decoration:none;display:inline-flex;align-items:center;gap:6px;padding:9px 14px}

/* ---- cards (articles) ---- */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px;margin:0 0 24px}
.card{display:flex;flex-direction:column;background:var(--panel);border:1px solid var(--line);border-radius:10px;overflow:hidden;text-decoration:none;color:var(--txt);transition:border-color .15s,transform .15s}
.card:hover{border-color:var(--accent);transform:translateY(-2px)}
.card img{width:100%;height:auto;aspect-ratio:16/9;object-fit:cover;display:block;background:var(--panel-2)}
.card .cmedia{position:relative;display:block;aspect-ratio:16/9;overflow:hidden;background:var(--panel-2)}
.card .cmedia img,.card .cmedia video{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;display:block}
.card .cmedia img{transition:transform .6s cubic-bezier(.2,.7,.2,1)}
.card .cmedia video{opacity:0;transition:opacity .35s ease}
.card:hover .cmedia img,.card:focus-visible .cmedia img{transform:scale(1.04)}
.card.playing .cmedia video{opacity:1}
.card.playing .cmedia img{transform:scale(1.04)}
.card .cmedia::after{content:'';position:absolute;inset:0;background:linear-gradient(to top,rgba(11,14,20,.35),transparent 45%);pointer-events:none}
@media(prefers-reduced-motion:reduce){.card .cmedia img{transition:none}.card:hover .cmedia img{transform:none}}
.card .cbody{padding:13px 14px 15px;display:flex;flex-direction:column;gap:6px;flex:1}
.card .ctitle{font-weight:700;font-size:15px;line-height:1.35}
.card .cdesc{font-size:12.5px;color:var(--muted);line-height:1.55;flex:1}
.card .cmeta{font-size:11px;color:var(--muted);display:flex;gap:10px;align-items:center}
.card .cmeta i{color:var(--accent);font-size:11px}
.card.noimg .cbody{padding-top:16px}

.art-hero{margin:14px 0 22px}
.art-hero img{width:100%;height:auto;aspect-ratio:16/9;object-fit:cover;border-radius:10px;border:1px solid var(--line);display:block}
.art-meta{display:flex;gap:14px;flex-wrap:wrap;font-size:12.5px;color:var(--muted);margin:0 0 6px;align-items:center}
.art-meta i{color:var(--accent);margin-right:4px}
.byline{display:flex;align-items:center;gap:10px}
.avatar{width:30px;height:30px;border-radius:50%;background:radial-gradient(circle at 35% 30%,#ffe082,var(--accent));display:inline-flex;align-items:center;justify-content:center;color:#3a2a00;font-weight:800;font-size:12px}

.cta-box{background:linear-gradient(135deg,var(--panel),var(--panel-2));border:1px solid var(--line);border-radius:10px;padding:18px 20px;margin:28px 0;display:flex;gap:16px;align-items:center;flex-wrap:wrap}
.cta-box .ctext{flex:1;min-width:200px}
.cta-box b{display:block;font-size:15px;margin-bottom:4px;color:var(--txt)}
.cta-box p{margin:0;font-size:13px;color:var(--muted)}
.cta-box .ctl{text-decoration:none;display:inline-flex;align-items:center;gap:6px;padding:10px 16px;font-weight:700}

.faq-wrap{margin:0 0 24px}
.faq-wrap details.faq>summary{font-size:15px}
.faq-wrap .faq-a{font-size:14.5px}

/* ---- footer ---- */
.site-foot{border-top:1px solid var(--line);padding:30px 16px 40px;color:var(--muted);font-size:13px;margin-top:20px;background:var(--panel)}
.site-foot .inner{max-width:1060px;margin:0 auto;display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:26px;align-items:start;justify-content:start}
.site-foot .inner.fine{display:block;margin-top:22px;padding-top:14px;border-top:1px solid var(--line);font-size:11.5px;line-height:1.6}
.site-foot .fcol{display:flex;flex-direction:column;gap:2px}
.site-foot .fcol b{display:block;color:var(--txt);font-size:12px;text-transform:uppercase;letter-spacing:.8px;margin:0 0 8px;line-height:28px}
.site-foot .fcol p{margin:0 0 10px;line-height:1.6;font-size:13px}
.site-foot a{color:var(--muted);text-decoration:none}
.site-foot .fcol a{display:inline-flex;align-items:center;min-height:28px;padding:0;width:max-content;font-size:13.5px;line-height:28px}
.site-foot a:hover{color:var(--accent)}
.site-foot .fcol a.bmc{display:inline-flex;align-items:center;gap:6px;background:var(--accent);color:#1a1a1a;font-weight:700;padding:9px 14px;margin-top:6px;border-radius:8px;width:max-content;min-height:36px}
.site-foot .fcol a.bmc:hover{color:#1a1a1a;filter:brightness(1.05)}

/* ---- about ---- */
.about-hero{display:grid;gap:20px;align-items:center;margin:10px 0 24px}
@media(min-width:720px){.about-hero{grid-template-columns:1.2fr 1fr}}
.about-hero img{width:100%;height:auto;aspect-ratio:16/9;object-fit:cover;border-radius:12px;border:1px solid var(--line)}
.stat-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(130px,1fr));gap:10px;margin:0 0 24px}
.stat{background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:14px;text-align:center}
.stat b{display:block;font-size:24px;color:var(--accent)}
.stat span{font-size:12px;color:var(--muted)}
/* narrow phones: let the element hero text drop under the symbol tile */
@media(max-width:440px){.el-hero{flex-wrap:wrap}.el-hero h1{font-size:26px}.el-sym{width:72px;height:72px;font-size:28px}}
/* ---- compare pages ---- */
.cmp-grid{display:grid;gap:18px;margin:22px 0}
@media(min-width:760px){.cmp-grid{grid-template-columns:1fr 1fr}}
.cmp-side{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:16px}
.cmp-side .el-hero{margin:0 0 10px}.cmp-side .el-sym{width:56px;height:56px;font-size:22px}
.cmp-side h2 a{color:var(--txt);text-decoration:none}.cmp-side h2 a:hover{color:var(--accent)}
.cmp-side p{font-size:14.5px}.cmp-side .dyk li{font-size:13.5px}

/* ---- page feedback ---- */
.feedback{display:flex;gap:10px;align-items:center;flex-wrap:wrap;background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:12px 16px;margin:10px 0 30px;font-size:14px;color:var(--muted)}
.feedback .fb-q{margin-right:auto}.feedback a{color:#8fc6de}
.feedback .ctl{display:inline-flex;align-items:center;gap:6px;padding:8px 12px}
/* ---- weekly challenge ---- */
.wq{margin:18px 0 28px}.wq-meta{font-size:12px;color:var(--muted);margin-bottom:6px}
.wq-q{font-size:19px;margin:0 0 14px}
.wq-opts{display:grid;gap:8px;grid-template-columns:1fr}@media(min-width:600px){.wq-opts{grid-template-columns:1fr 1fr}}
.wq-opt{text-align:left;padding:12px 14px;font-size:15px;line-height:1.3;white-space:normal}
.wq-opt.right{border-color:var(--good);background:#1d4a2b}.wq-opt.wrong{border-color:var(--bad);background:#4a1d1d}
.wq-opt:disabled{cursor:default;opacity:.85}
.wq-fb{margin-top:12px;font-size:14.5px;display:flex;gap:10px;align-items:center;flex-wrap:wrap}.wq-fb a{color:#8fc6de}
.wcode{text-align:center;background:var(--panel);border:1px dashed var(--accent);border-radius:10px;padding:14px;margin:14px 0}
.wcode-val{font-family:ui-monospace,monospace;font-size:36px;font-weight:800;letter-spacing:6px;color:var(--accent);margin:4px 0}
#wstartbox input.ctl{font-size:14px}