.gcbt-shell,.gcbt-exam-shell{
  --gcbt-primary:#3e3693;--gcbt-secondary:#2457c6;--gcbt-gold:#ffc000;--gcbt-cream:#fffdf8;
  --gcbt-ink:#16122c;--gcbt-muted:#5c5780;--gcbt-mint:#0f766e;--gcbt-rose:#be185d;--gcbt-sky:#0369a1;
  box-sizing:border-box;max-width:1120px;margin:0 auto;padding:16px;color:var(--gcbt-ink);
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,sans-serif;overflow-x:hidden
}
.gcbt-shell *,.gcbt-exam-shell *{box-sizing:border-box}
.gcbt-kicker{display:inline-flex;align-items:center;gap:6px;background:var(--gcbt-gold);color:#3e3693;font-size:11px;font-weight:800;letter-spacing:.06em;text-transform:uppercase;padding:5px 10px;border-radius:999px}
.gcbt-btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;background:var(--gcbt-primary);color:#fff;text-decoration:none;border:0;border-radius:12px;padding:12px 16px;font-weight:800;cursor:pointer;font:inherit;min-height:44px;line-height:1.2;transition:transform .15s ease,filter .15s ease}
.gcbt-btn:hover{color:#fff;filter:brightness(1.08);transform:translateY(-1px)}
.gcbt-btn:disabled{opacity:.45;cursor:not-allowed;transform:none}
.gcbt-btn-ghost,.gcbt-btn-light{background:#fff;color:var(--gcbt-primary);border:2px solid #ece7ff}
.gcbt-btn-gold{background:var(--gcbt-gold);color:#3e3693}
.gcbt-btn-mint{background:var(--gcbt-mint);color:#fff}
.gcbt-form label,.gcbt-login-card label{display:block;font-size:13px;font-weight:800;margin:0 0 12px;color:var(--gcbt-ink)}
.gcbt-form input,.gcbt-form select,.gcbt-form textarea,.gcbt-login-card input[type=text],.gcbt-login-card input[type=password],.gcbt-login-card input[type=email]{width:100%;margin-top:6px;padding:12px 14px;border:2px solid #e4def8;border-radius:12px;font:inherit;background:#fff;min-height:44px}
.gcbt-form input:focus,.gcbt-form select:focus,.gcbt-form textarea:focus,.gcbt-login-card input:focus{outline:0;border-color:var(--gcbt-primary);box-shadow:0 0 0 4px rgba(62,54,147,.12)}
.gcbt-form button[type=submit],.gcbt-login-card button[type=submit],.gcbt-login-card input[type=submit]{width:100%;background:var(--gcbt-primary);color:#fff;border:0;border-radius:12px;padding:14px;font-weight:800;cursor:pointer;min-height:48px}
.gcbt-alert{padding:12px 14px;border-radius:14px;margin:0 0 16px;font-weight:600}
.gcbt-alert.is-error{background:#fee2e2;color:#991b1b}
.gcbt-alert.is-ok{background:#dcfce7;color:#14532d}
.gcbt-or{text-align:center;color:var(--gcbt-muted);margin:16px 0 8px;font-size:13px;font-weight:700}
.gcbt-help{font-size:12px;color:var(--gcbt-muted);margin:16px 0 0;line-height:1.5}

.gcbt-login-wrap{background:linear-gradient(160deg,#2d2778 0%,#3e3693 42%,#2457c6 100%);border-radius:24px;padding:28px 16px;margin:8px 0 24px}
.gcbt-login-card{max-width:440px;margin:0 auto;background:#fff;border:0;border-radius:24px;padding:28px 24px;box-shadow:0 24px 50px rgba(16,10,48,.28)}
.gcbt-brand{display:flex;gap:12px;align-items:center;margin:0 0 18px}
.gcbt-brand img{width:56px;height:56px;object-fit:contain;border-radius:14px;background:#f6f4ff;padding:6px}
.gcbt-mark{width:56px;height:56px;border-radius:16px;background:linear-gradient(135deg,#3e3693,#2457c6);color:#ffc000;display:flex;align-items:center;justify-content:center;font-weight:900;font-size:14px}
.gcbt-login-card h2{margin:0 0 8px;font-size:26px}
.gcbt-login-card > p{color:var(--gcbt-muted);margin:0 0 16px}

.gcbt-hero{display:flex;justify-content:space-between;gap:16px;align-items:flex-start;background:linear-gradient(135deg,var(--gcbt-primary),#5b52c4 55%,var(--gcbt-secondary));color:#fff;border-radius:24px;padding:24px;margin:0 0 20px;box-shadow:0 16px 40px rgba(62,54,147,.25)}
.gcbt-hero h2{margin:8px 0 6px;color:#fff;font-size:28px}
.gcbt-hero p{margin:0;color:#f4faa0;max-width:540px}
.gcbt-hero .gcbt-btn-ghost{border-color:rgba(255,255,255,.35);background:rgba(255,255,255,.12);color:#fff}

.gcbt-tabs{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 18px}
.gcbt-tabs a{display:inline-flex;align-items:center;min-height:40px;padding:8px 14px;border-radius:999px;background:#f3f0ff;color:var(--gcbt-primary);text-decoration:none;font-weight:800;font-size:13px}
.gcbt-tabs a.is-on{background:var(--gcbt-primary);color:#fff}
.gcbt-section-title{display:flex;align-items:center;gap:10px;margin:8px 0 14px;font-size:18px}
.gcbt-section-title span{width:10px;height:10px;border-radius:50%;background:var(--gcbt-gold)}

.gcbt-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(270px,1fr));gap:16px}
.gcbt-card{background:#fff;border:1px solid #eee8ff;border-radius:22px;padding:18px;display:flex;flex-direction:column;gap:10px;box-shadow:0 10px 30px rgba(62,54,147,.08);position:relative;overflow:hidden;min-width:0}
.gcbt-card:before{content:"";position:absolute;left:0;top:0;bottom:0;width:6px;background:var(--gcbt-mint)}
.gcbt-card.gcbt-graded:before{background:var(--gcbt-gold)}
.gcbt-card-icon{width:44px;height:44px;border-radius:14px;display:flex;align-items:center;justify-content:center;font-size:20px;background:#ecfdf5;color:#0f766e}
.gcbt-card.gcbt-graded .gcbt-card-icon{background:#fff7cc;color:#92400e}
.gcbt-card-top{display:flex;justify-content:space-between;align-items:center;gap:8px}
.gcbt-card-top em{font-style:normal;background:#ecfdf5;color:#0f766e;font-size:11px;font-weight:800;padding:4px 10px;border-radius:99px}
.gcbt-card.gcbt-graded .gcbt-card-top em{background:#fff7cc;color:#92400e}
.gcbt-time-chip{background:#f3f0ff;color:var(--gcbt-primary);font-size:12px;font-weight:800;padding:4px 10px;border-radius:99px;white-space:nowrap}
.gcbt-card h3{margin:0;font-size:18px;line-height:1.3}
.gcbt-card p{margin:0;font-size:14px;color:var(--gcbt-muted);line-height:1.45}
.gcbt-chips{display:flex;flex-wrap:wrap;gap:6px;padding:0;margin:0;list-style:none}
.gcbt-chips li{background:#f6f4ff;color:#3e3693;font-size:12px;font-weight:700;padding:5px 10px;border-radius:999px}
.gcbt-card-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:auto}
.gcbt-card-actions .gcbt-btn{flex:1;min-width:120px}

.gcbt-briefing{display:grid;grid-template-columns:1.35fr .75fr;gap:16px;background:#fff;border:1px solid #eee8ff;border-radius:24px;padding:22px;margin:0 0 22px;box-shadow:0 12px 32px rgba(62,54,147,.08)}
.gcbt-meta{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}
.gcbt-meta span{background:#f6f4ff;border:0;border-radius:99px;padding:6px 12px;font-size:12px;font-weight:800;color:var(--gcbt-primary)}
.gcbt-instructions{white-space:pre-wrap;background:#fffdf5;border-radius:16px;padding:14px;font-size:14px;line-height:1.5}
.gcbt-briefing form{display:flex;flex-direction:column;gap:12px;justify-content:center;background:linear-gradient(180deg,#3e3693,#2457c6);color:#fff;border-radius:20px;padding:20px}
.gcbt-briefing form .gcbt-btn{background:#ffc000;color:#3e3693}
.gcbt-briefing form small{color:#f4faa0}
.gcbt-empty{grid-column:1/-1;padding:28px;text-align:center;background:#f6f4ff;border-radius:20px;color:var(--gcbt-muted)}

.gcbt-dash-band{display:flex;flex-wrap:wrap;gap:16px;align-items:center;background:linear-gradient(120deg,#3e3693,#2457c6);color:#fff;border-radius:24px;padding:22px;margin:20px 0;box-shadow:0 14px 32px rgba(62,54,147,.2)}
.gcbt-dash-band h3{margin:6px 0;color:#fff;font-size:22px}
.gcbt-dash-band p{margin:0;color:#f4faa0;max-width:420px}
.gcbt-dash-stats{background:rgba(255,255,255,.14);border-radius:16px;padding:12px 18px;text-align:center;min-width:92px}
.gcbt-dash-stats b{display:block;font-size:28px}
.gcbt-dash-band .gcbt-btn{background:#ffc000;color:#3e3693}

.gcbt-exam-shell{max-width:1200px;padding:12px 12px 28px}
.gcbt-exam-bar{display:flex;align-items:center;gap:12px;background:#16122c;color:#fff;border-radius:18px;padding:12px 14px;position:sticky;top:8px;z-index:20;box-shadow:0 10px 28px rgba(0,0,0,.18)}
.gcbt-exam-bar small{display:block;color:#f4faa0;font-size:12px}
.gcbt-exam-bar strong{display:block;font-size:15px;line-height:1.3}
.gcbt-timer{margin-left:auto;font-size:26px;font-weight:900;font-variant-numeric:tabular-nums;background:#111;color:#ffc000;padding:8px 14px;border-radius:14px;min-width:118px;text-align:center;letter-spacing:.04em}
.gcbt-timer.is-warn{background:#c00000;color:#fff;animation:gcbtPulse 1s infinite}
@keyframes gcbtPulse{50%{opacity:.72}}
.gcbt-progress{height:8px;background:#ece7ff;border-radius:99px;margin:12px 0 0;overflow:hidden}
.gcbt-progress > i{display:block;height:100%;width:0;background:linear-gradient(90deg,#ffc000,#3e3693);border-radius:99px;transition:width .2s ease}
.gcbt-exam-layout{display:grid;grid-template-columns:220px 1fr;gap:16px;margin-top:16px}
.gcbt-nav{background:#fff;border:1px solid #eee8ff;border-radius:20px;padding:14px;display:flex;flex-wrap:wrap;gap:8px;align-content:flex-start;max-height:70vh;overflow:auto}
.gcbt-nav-legend{width:100%;display:flex;flex-wrap:wrap;gap:8px;font-size:11px;color:var(--gcbt-muted);margin:0 0 6px}
.gcbt-nav-legend b{display:inline-block;width:10px;height:10px;border-radius:3px;margin-right:4px;vertical-align:middle}
.gcbt-nav button{width:42px;height:42px;border-radius:12px;border:2px solid #e4def8;background:#fff;cursor:pointer;font-weight:800;color:var(--gcbt-ink)}
.gcbt-nav button.is-current{background:var(--gcbt-primary);color:#fff;border-color:var(--gcbt-primary)}
.gcbt-nav button.is-answered{background:#dcfce7;border-color:#86efac}
.gcbt-nav button.is-flagged{background:#fef3c7;border-color:#f59e0b}
.gcbt-stage{background:#fff;border:1px solid #eee8ff;border-radius:24px;padding:24px;min-height:360px;box-shadow:0 10px 28px rgba(62,54,147,.06);min-width:0}
.gcbt-q-meta{display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap;color:var(--gcbt-muted);font-size:13px;font-weight:700;margin:0 0 10px}
.gcbt-stage h3{margin:0 0 18px;font-size:22px;line-height:1.4}
.gcbt-choices{display:flex;flex-direction:column;gap:10px}
.gcbt-choices label{display:flex;gap:12px;align-items:flex-start;border:2px solid #eee8ff;border-radius:16px;padding:14px;cursor:pointer;min-height:52px}
.gcbt-choices label.is-on{border-color:var(--gcbt-primary);background:#f6f4ff;box-shadow:0 0 0 4px rgba(62,54,147,.08)}
.gcbt-letter{flex:0 0 32px;width:32px;height:32px;border-radius:10px;background:#ece7ff;color:var(--gcbt-primary);display:flex;align-items:center;justify-content:center;font-weight:900}
.gcbt-choices label.is-on .gcbt-letter{background:var(--gcbt-primary);color:#fff}
.gcbt-stage textarea,.gcbt-fill{width:100%;min-height:88px;padding:14px;border:2px solid #e4def8;border-radius:16px;font:inherit}
.gcbt-stage-nav{display:flex;justify-content:space-between;gap:8px;margin-top:22px;flex-wrap:wrap}
.gcbt-flag{background:#fff7cc;border:0;color:#92400e;font-weight:800;cursor:pointer;border-radius:12px;padding:10px 14px;min-height:44px}

.gcbt-result-hero{text-align:center;padding:32px 18px;border-radius:24px;background:#f6f4ff;margin:0 0 20px}
.gcbt-result-hero.is-pass{background:linear-gradient(180deg,#ecfdf3,#fff)}
.gcbt-result-hero.is-fail{background:linear-gradient(180deg,#fef2f2,#fff)}
.gcbt-score-ring{margin:16px auto;width:168px;height:168px;border-radius:50%;border:12px solid var(--gcbt-gold);display:flex;flex-direction:column;align-items:center;justify-content:center;background:#fff;box-shadow:0 10px 24px rgba(0,0,0,.06)}
.gcbt-score-ring b{font-size:36px}
.gcbt-posted{display:inline-block;background:#3e3693;color:#fff;padding:10px 16px;border-radius:12px;margin:12px 0;font-weight:700}
.gcbt-posted.is-practice{background:#0f766e}
.gcbt-review{display:grid;gap:12px}
.gcbt-review h3{margin:0 0 4px}
.gcbt-review article{background:#fff;border:1px solid #eee;border-radius:18px;padding:16px}
.gcbt-review article.is-right{border-color:#86efac;background:#f0fdf4}
.gcbt-review article.is-wrong{border-color:#fca5a5;background:#fff7f7}
.gcbt-review article header{display:flex;gap:10px;align-items:center;margin:0 0 8px;flex-wrap:wrap}
.gcbt-review ul{list-style:none;padding:0;margin:8px 0}
.gcbt-review li{padding:6px 0}
.gcbt-review li.ok{color:#166534;font-weight:800}
.gcbt-review li.picked{color:#991b1b;text-decoration:line-through}
.gcbt-review aside{background:#fffbeb;padding:10px 12px;border-radius:12px;margin-top:8px}

.gcbt-exam-shell[data-lock="1"] .gcbt-stage{-webkit-user-select:none;user-select:none}

@media (max-width:800px){
  .gcbt-shell,.gcbt-exam-shell{padding:12px}
  .gcbt-exam-layout,.gcbt-briefing{grid-template-columns:1fr}
  .gcbt-exam-bar{flex-wrap:wrap}
  .gcbt-timer{margin-left:0;width:100%;font-size:28px}
  .gcbt-hero,.gcbt-dash-band{flex-direction:column}
  .gcbt-nav{max-height:none;flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;padding-bottom:8px}
  .gcbt-nav button{flex:0 0 42px}
  .gcbt-login-wrap{padding:18px 12px;border-radius:18px}
  .gcbt-card-actions .gcbt-btn{flex:1 1 100%}
  .gcbt-stage{padding:16px}
  .gcbt-stage h3{font-size:18px}
}