/* SDChat Hub shared Apple-like design system */
:root{
  --hub-bg:#f5f7fb;
  --hub-bg2:#eef3f9;
  --hub-card:rgba(255,255,255,.82);
  --hub-card-solid:#fff;
  --hub-soft:#f8fafc;
  --hub-text:#111827;
  --hub-muted:#667085;
  --hub-line:rgba(16,24,40,.10);
  --hub-blue:#2563eb;
  --hub-cyan:#06b6d4;
  --hub-green:#16a34a;
  --hub-amber:#d97706;
  --hub-red:#dc2626;
  --hub-shadow:0 18px 55px rgba(16,24,40,.10);
  --hub-shadow-soft:0 8px 26px rgba(16,24,40,.07);
  --hub-radius-xl:32px;
  --hub-radius:24px;
  --hub-radius-sm:16px;
}
[data-theme="dark"]{
  --hub-bg:#0b1220;
  --hub-bg2:#111827;
  --hub-card:rgba(22,31,47,.82);
  --hub-card-solid:#161f2f;
  --hub-soft:#1d2738;
  --hub-text:#f8fafc;
  --hub-muted:#b8c2d3;
  --hub-line:rgba(255,255,255,.11);
  --hub-shadow:0 24px 70px rgba(0,0,0,.34);
  --hub-shadow-soft:0 10px 32px rgba(0,0,0,.24);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body.hub-app{margin:0;min-height:100vh;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;color:var(--hub-text);background:radial-gradient(circle at 15% -10%,rgba(37,99,235,.16),transparent 34%),radial-gradient(circle at 90% 0%,rgba(6,182,212,.12),transparent 30%),linear-gradient(180deg,var(--hub-bg),var(--hub-bg2));}
a{color:inherit;text-decoration:none}
.hub-shell{width:min(1120px,calc(100% - 32px));margin:0 auto;padding:18px 0 44px;position:relative}
.hub-top{position:sticky;top:0;z-index:20;margin:0 -16px 18px;padding:12px 16px;display:flex;align-items:center;justify-content:space-between;gap:12px;background:color-mix(in srgb,var(--hub-bg) 86%,transparent);backdrop-filter:blur(18px);border-bottom:1px solid color-mix(in srgb,var(--hub-line) 72%,transparent)}
.hub-brand{display:flex;align-items:center;gap:11px;font-weight:900;letter-spacing:-.035em;min-width:0}.hub-logo{width:40px;height:40px;border-radius:15px;display:grid;place-items:center;color:#fff;background:linear-gradient(135deg,var(--hub-blue),var(--hub-cyan));box-shadow:0 10px 24px rgba(37,99,235,.22);flex:0 0 auto}.hub-brand span:last-child{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.hub-brand small{display:block;color:var(--hub-muted);font-weight:700;letter-spacing:0;font-size:12px;margin-top:1px}
.hub-actions{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.hub-btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:1px solid var(--hub-line);border-radius:16px;background:var(--hub-card-solid);color:var(--hub-text);padding:10px 14px;font-weight:850;font-size:14px;box-shadow:var(--hub-shadow-soft);cursor:pointer}.hub-btn.primary{background:#111827;color:#fff;border-color:#111827}.hub-btn.ghost{background:var(--hub-soft);box-shadow:none}[data-theme="dark"] .hub-btn.primary{background:linear-gradient(135deg,var(--hub-blue),var(--hub-cyan));color:#fff;border-color:transparent}
.hub-hero{border:1px solid var(--hub-line);background:var(--hub-card);backdrop-filter:blur(22px);box-shadow:var(--hub-shadow);border-radius:var(--hub-radius-xl);padding:30px;margin-bottom:18px;position:relative;overflow:hidden}.hub-hero:after{content:"";position:absolute;right:-90px;top:-110px;width:270px;height:270px;border-radius:50%;background:radial-gradient(circle,rgba(37,99,235,.14),transparent 65%);pointer-events:none}.hub-hero>*{position:relative;z-index:1}.hub-kicker{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-bottom:14px;color:var(--hub-muted);font-weight:850;font-size:14px}.hub-kicker span+span:before{content:"·";margin-right:10px;color:color-mix(in srgb,var(--hub-muted) 65%,transparent)}
.hub-title{margin:0;font-size:clamp(36px,5vw,64px);line-height:.98;letter-spacing:-.065em;font-weight:850}.hub-lead{margin:13px 0 0;max-width:680px;color:var(--hub-muted);font-size:18px;line-height:1.42}
.hub-card{border:1px solid var(--hub-line);background:var(--hub-card-solid);box-shadow:var(--hub-shadow-soft);border-radius:var(--hub-radius);padding:18px}.hub-grid{display:grid;grid-template-columns:repeat(12,1fr);gap:14px}.hub-section-title{font-size:26px;letter-spacing:-.045em;margin:28px 0 12px}.hub-tag{display:inline-flex;border:1px solid var(--hub-line);background:var(--hub-soft);border-radius:999px;padding:7px 10px;color:var(--hub-muted);font-weight:850;font-size:12px}.hub-empty{border:1px dashed var(--hub-line);background:var(--hub-card-solid);border-radius:var(--hub-radius);padding:30px;text-align:center;color:var(--hub-muted)}
@media(max-width:640px){.hub-shell{width:100%;padding:0 10px 30px}.hub-top{margin:0 -10px 12px;padding:10px}.hub-brand small{display:none}.hub-logo{width:36px;height:36px;border-radius:13px}.hub-actions .hub-btn:not(.keep){display:none}.hub-hero{padding:23px;border-radius:27px}.hub-title{font-size:40px}.hub-lead{font-size:16px;max-width:94%}.hub-grid{grid-template-columns:1fr;gap:10px}.hub-btn{min-height:42px}.hub-section-title{font-size:24px;margin-top:24px}}


/* Global dark-theme text hardening — prevent native button/input black text */
button,input,select,textarea{font:inherit;color:inherit}
.hub-app button,.hub-app input,.hub-app select,.hub-app textarea{color:var(--hub-text)}
.hub-app input::placeholder,.hub-app textarea::placeholder{color:var(--hub-muted);opacity:.9}
.hub-app .hub-btn,.hub-app .cal-btn,.hub-app .mini-btn,.hub-app .learn-tab,.hub-app .course-list-btn,.hub-app .reminder-chip,.hub-app .cat,.hub-app .file-card,.hub-app .day{color:var(--hub-text)}
.hub-app .hub-btn.ghost,.hub-app .cal-btn.ghost,.hub-app .cat,.hub-app .hub-tag,.hub-app .pill{color:var(--hub-muted)}
[data-theme="dark"] .hub-app .hub-btn.primary,[data-theme="dark"] .hub-app .cal-btn.primary,[data-theme="dark"] .hub-app .learn-tab.active,[data-theme="dark"] .hub-app .cat.active,[data-theme="dark"] .hub-app .reminder-chip.active{background:linear-gradient(135deg,var(--hub-blue),var(--hub-cyan))!important;color:#fff!important;border-color:transparent!important}
[data-theme="dark"] .hub-app .day,[data-theme="dark"] .hub-app .file-card,[data-theme="dark"] .hub-app .course-list-btn,[data-theme="dark"] .hub-app .learn-card,[data-theme="dark"] .hub-app .agenda-item,[data-theme="dark"] .hub-app .summary-card,[data-theme="dark"] .hub-app .stat{color:var(--hub-text)!important}
[data-theme="dark"] .hub-app .hub-muted,[data-theme="dark"] .hub-app .course-desc,[data-theme="dark"] .hub-app .agenda-meta,[data-theme="dark"] .hub-app .month-sub,[data-theme="dark"] .hub-app .selected-date,[data-theme="dark"] .hub-app .empty{color:var(--hub-muted)!important}
[data-theme="dark"] .hub-app .leaflet-popup-content{color:#111827!important}