:root{--bg:#f5f6f8;--surface:#fff;--surface-alt:#f0f1f4;--text:#1a1d23;--text-muted:#6b7280;--border:#e3e5ea;--accent:#2563eb;--accent-dark:#1d4ed8;--accent-contrast:#fff;--accent-soft:#e8f0fe;--correct:#16a34a;--correct-soft:#dcfce7;--incorrect:#dc2626;--incorrect-soft:#fee2e2;--flag:#d97706;--flag-soft:#fef3c7;--radius-sm:8px;--radius-md:14px;--radius-lg:20px;--shadow:0 1px 2px #1018280f, 0 1px 3px #10182814;--safe-top:env(safe-area-inset-top,0px);--safe-bottom:env(safe-area-inset-bottom,0px);--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light}*{box-sizing:border-box}html,body{background:var(--bg);color:var(--text);-webkit-tap-highlight-color:transparent;margin:0;padding:0}body{overscroll-behavior-y:none;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;font-size:16px;line-height:1.45}#root{flex-direction:column;min-height:100vh;display:flex}button{font-family:inherit}a{color:inherit}h1,h2,h3,p{margin:0}.app-shell{flex-direction:column;flex:1;width:100%;max-width:640px;margin:0 auto;display:flex}.page{padding:calc(16px + var(--safe-top)) 16px calc(16px + var(--safe-bottom));flex-direction:column;flex:1;gap:16px;display:flex}.page-title{font-size:22px;font-weight:700}.page-subtitle{color:var(--text-muted);font-size:14px}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);box-shadow:var(--shadow);padding:16px}.btn{border-radius:var(--radius-sm);cursor:pointer;touch-action:manipulation;border:1px solid #0000;justify-content:center;align-items:center;gap:8px;min-height:44px;padding:12px 18px;font-size:15px;font-weight:600;transition:opacity .15s,background-color .15s;display:inline-flex}.btn:disabled{opacity:.45;cursor:not-allowed}.btn-primary{background:var(--accent);color:var(--accent-contrast)}.btn-primary:active:not(:disabled){background:var(--accent-dark)}.btn-secondary{background:var(--surface);color:var(--text);border-color:var(--border)}.btn-secondary:active:not(:disabled){background:var(--surface-alt)}.btn-ghost{color:var(--text-muted);background:0 0;border-color:#0000;padding:10px 12px}.btn-danger{color:var(--incorrect);border-color:var(--incorrect-soft);background:0 0}.btn-block{width:100%}.chip{background:var(--surface-alt);color:var(--text-muted);white-space:nowrap;border-radius:999px;align-items:center;gap:4px;padding:4px 10px;font-size:12px;font-weight:600;display:inline-flex}.chip-accent{background:var(--accent-soft);color:var(--accent-dark)}.progress-track{background:var(--surface-alt);border-radius:999px;height:6px;overflow:hidden}.progress-fill{background:var(--accent);border-radius:999px;height:100%;transition:width .2s}.empty-state{text-align:center;color:var(--text-muted);padding:48px 16px}.spinner{border:3px solid var(--border);border-top-color:var(--accent);border-radius:50%;width:28px;height:28px;margin:0 auto;animation:.7s linear infinite spin}@keyframes spin{to{transform:rotate(360deg)}}.bottom-bar{margin:16px -16px calc(-16px - var(--safe-bottom));padding:10px 16px calc(14px + var(--safe-bottom));background:linear-gradient(to top, var(--bg) 70%, transparent);gap:10px;display:flex;position:sticky;bottom:0}.bottom-bar .btn{flex:1}.error-banner{background:var(--incorrect-soft);color:var(--incorrect);border-radius:var(--radius-sm);padding:12px 14px;font-size:14px}.upload-card{text-align:center;flex-direction:column;gap:8px;display:flex}.import-tabs{background:var(--surface-alt);border-radius:var(--radius-sm);gap:3px;margin-bottom:4px;padding:3px;display:flex}.import-tab{border-radius:calc(var(--radius-sm) - 2px);color:var(--text-muted);cursor:pointer;background:0 0;border:none;flex:1;min-height:36px;padding:8px;font-size:13px;font-weight:600}.import-tab--active{background:var(--surface);color:var(--text);box-shadow:var(--shadow)}.paste-form{flex-direction:column;gap:8px;display:flex}.paste-form__name{border:1.5px solid var(--border);border-radius:var(--radius-sm);min-height:44px;padding:10px 12px;font-size:14px}.paste-form__textarea{border:1.5px solid var(--border);border-radius:var(--radius-sm);resize:vertical;min-height:140px;padding:10px 12px;font-family:inherit;font-size:14px}.upload-card__input{opacity:0;width:1px;height:1px;position:absolute;overflow:hidden}.btn-disabled{opacity:.6;pointer-events:none}.set-list{flex-direction:column;gap:10px;display:flex}.set-card{flex-direction:column;gap:10px;padding:14px;display:flex}.set-card__open{text-align:left;cursor:pointer;width:100%;color:inherit;font:inherit;background:0 0;border:none;justify-content:space-between;align-items:center;gap:10px;padding:0;display:flex}.set-card__main{flex-direction:column;gap:4px;min-width:0;display:flex}.set-card__name{white-space:nowrap;text-overflow:ellipsis;font-size:16px;font-weight:700;overflow:hidden}.set-card__meta{color:var(--text-muted);gap:6px;font-size:13px;display:flex}.set-card__chevron{color:var(--text-muted);flex:none;font-size:24px;line-height:1}.set-card__practice{min-height:40px;padding:10px;font-size:14px}.set-card__actions{justify-content:center;gap:20px;display:flex}.set-card__link{color:var(--text-muted);cursor:pointer;background:0 0;border:none;padding:4px;font-size:13px;font-weight:600;text-decoration:none}.set-card__link--danger{color:var(--incorrect)}.home-back{align-self:flex-start;padding-left:0;font-weight:600}.stat-row{grid-template-columns:repeat(3,1fr);gap:10px;display:grid}.stat-chip{text-align:center;padding:14px 8px}.stat-chip__value{color:var(--accent-dark);font-size:20px;font-weight:700}.stat-chip__label{color:var(--text-muted);margin-top:2px;font-size:12px}.mode-section{flex-direction:column;gap:12px;display:flex}.mode-card{flex-direction:column;gap:10px;display:flex}.mode-card h3{font-size:17px}.mode-card__actions{gap:10px;display:flex}.mode-card__actions .btn{flex:1}.domain-list__title{margin-bottom:10px;font-size:15px}.domain-list{flex-direction:column;gap:8px;display:flex}.domain-list__row{border-bottom:1px solid var(--border);justify-content:space-between;padding-bottom:8px;font-size:14px;display:flex}.domain-list__row:last-child{border-bottom:none;padding-bottom:0}.quiz-top-bar{z-index:5;background:var(--bg);padding-top:calc(10px + var(--safe-top));flex-direction:column;gap:8px;padding-bottom:8px;display:flex;position:sticky;top:0}.quiz-top-bar__row{justify-content:space-between;align-items:center;gap:8px;display:flex}.quiz-top-bar__exit{padding-left:0;font-weight:600}.quiz-top-bar__timer{font-variant-numeric:tabular-nums;color:var(--text);font-size:15px;font-weight:700}.quiz-top-bar__timer--low{color:var(--incorrect)}.quiz-top-bar__picker{flex:1;justify-content:flex-start;font-weight:600}.quiz-top-bar__flag{flex:none}.quiz-top-bar__flag--active{color:var(--flag)}.sheet-backdrop{z-index:20;background:#11141c73;align-items:flex-end;display:flex;position:fixed;inset:0}.sheet{background:var(--surface);border-radius:var(--radius-lg) var(--radius-lg) 0 0;width:100%;max-width:640px;padding:10px 16px calc(16px + var(--safe-bottom));flex-direction:column;gap:14px;max-height:80vh;margin:0 auto;display:flex}.sheet__handle{background:var(--border);border-radius:999px;width:40px;height:4px;margin:0 auto}.sheet__header{justify-content:space-between;align-items:baseline;display:flex}.sheet__header h2{font-size:18px}.sheet__grid{grid-template-columns:repeat(6,1fr);gap:8px;padding-bottom:4px;display:grid;overflow-y:auto}.picker-cell{aspect-ratio:1;border-radius:var(--radius-sm);border:1.5px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer;justify-content:center;align-items:center;font-size:14px;font-weight:600;display:flex;position:relative}.picker-cell--answered{background:var(--accent-soft);border-color:var(--accent);color:var(--accent-dark)}.picker-cell--current{border-color:var(--text);box-shadow:0 0 0 2px var(--text) inset}.picker-cell__flag{background:var(--flag);border-radius:50%;width:7px;height:7px;position:absolute;top:3px;right:3px}.question-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-lg);box-shadow:var(--shadow);flex-direction:column;gap:16px;padding:20px 16px;display:flex}.question-card__tags{flex-wrap:wrap;gap:6px;display:flex}.question-card__stem{white-space:pre-line;font-size:17px;font-weight:500}.question-card__options{flex-direction:column;gap:10px;display:flex}.option{text-align:left;background:var(--surface);border:1.5px solid var(--border);border-radius:var(--radius-md);width:100%;color:var(--text);cursor:pointer;align-items:flex-start;gap:12px;min-height:44px;padding:12px 14px;font-size:15px;transition:border-color .12s,background-color .12s;display:flex}.option:disabled{cursor:default}.option__letter{background:var(--surface-alt);width:26px;height:26px;color:var(--text-muted);border-radius:50%;flex:none;justify-content:center;align-items:center;font-size:13px;font-weight:700;display:flex}.option__text{flex:1}.option__mark{flex:none;font-weight:700}.option--selected{border-color:var(--accent);background:var(--accent-soft)}.option--selected .option__letter{background:var(--accent);color:var(--accent-contrast)}.option--correct{border-color:var(--correct);background:var(--correct-soft)}.option--correct .option__letter{background:var(--correct);color:#fff}.option--correct .option__mark{color:var(--correct)}.option--incorrect{border-color:var(--incorrect);background:var(--incorrect-soft)}.option--incorrect .option__letter{background:var(--incorrect);color:#fff}.option--incorrect .option__mark{color:var(--incorrect)}.question-card__explanation{background:var(--surface-alt);border-radius:var(--radius-md);color:var(--text);padding:14px;font-size:14px}.question-card__explanation-label{text-transform:uppercase;letter-spacing:.04em;color:var(--text-muted);margin-bottom:6px;font-size:12px;font-weight:700}.question-card__explanation p{white-space:pre-line}.quiz-page{padding-top:0}.quiz-page__submit-early{margin-top:-6px}.score-card{text-align:center;padding:24px 16px}.score-card__value{color:var(--accent-dark);font-size:40px;font-weight:800}.review-list{flex-direction:column;gap:12px;display:flex}.review-item .option{cursor:default}