:root{--bg:#f5f6f8;--surface:#fff;--border:#d9dce1;--text:#1c1f24;--text-muted:#6b7280;--accent:#2f6feb;--accent-2:#d2691e;--accent-contrast:#fff;--error-bg:#fdeceb;--error-border:#e5534b;--error-text:#8a1f16;--correct:#1a7f37;--wrong:#d1242f;--sans:system-ui, "Segoe UI", Roboto, sans-serif;--mono:ui-monospace, Consolas, monospace;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light}:root[data-theme=dark]{--bg:#14161a;--surface:#1b1e24;--border:#2e333c;--text:#e6e8eb;--text-muted:#9aa1ac;--accent:#5b9dff;--accent-2:#ffa057;--accent-contrast:#0b1220;--error-bg:#3a1c1c;--error-border:#e5534b;--error-text:#ffb4ac;--correct:#4ac26b;--wrong:#ff7b72;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}body{font:16px/1.5 var(--sans);background:var(--bg);color:var(--text);margin:0}.app{max-width:1100px;margin:0 auto;padding:16px 20px 48px}.site-header{align-items:center;gap:10px;margin-bottom:20px;display:flex}.site-header__brand{color:var(--accent);white-space:nowrap;font-size:15px;font-weight:700;text-decoration:none}.site-header__brand:hover{text-decoration:underline}.site-header__divider{color:var(--text-muted);font-weight:400}.site-header__title{color:var(--text-muted);white-space:nowrap;font-size:15px;font-weight:600}.toolbar-spacer{flex:1}.btn,.toggle-btn{border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer;border-radius:6px;padding:6px 12px;font-size:13px}.btn:hover,.toggle-btn:hover{border-color:var(--accent)}.icon-btn{padding:6px 10px}.btn--active{border-color:var(--accent);color:var(--accent);font-weight:600;text-decoration:none;display:inline-block}.nav-tabs{border-bottom:1px solid var(--border);flex-wrap:wrap;gap:4px;margin-bottom:20px;display:flex}.nav-tabs__tab{color:var(--text-muted);border-bottom:2px solid #0000;padding:8px 16px;font-size:14px;font-weight:600;text-decoration:none}.nav-tabs__tab:hover{color:var(--text)}.nav-tabs__tab--active{color:var(--accent);border-bottom-color:var(--accent)}.app__main{min-height:400px}.split-layout{grid-template-columns:240px 1fr;align-items:start;gap:24px;display:grid}@media (width<=720px){.split-layout{grid-template-columns:1fr}}.side-list{border:1px solid var(--border);background:var(--surface);border-radius:8px;flex-direction:column;gap:2px;display:flex;overflow:hidden}.side-list__item{color:var(--text);border-left:3px solid #0000;align-items:center;gap:8px;padding:8px 10px;font-size:13px;text-decoration:none;display:flex}.side-list__item:hover{background:var(--bg)}.side-list__item--active{border-left-color:var(--accent);background:var(--bg);font-weight:600}.side-list__index{color:var(--text-muted);min-width:14px;font-size:11px}.side-list__label{flex:1}.side-list__check{color:var(--correct)}.grammar-view{background:var(--surface);border:1px solid var(--border);border-radius:8px;padding:20px 24px}.grammar-view__header{justify-content:space-between;align-items:center;gap:12px;display:flex}.grammar-view__header h2{margin:0}.grammar-view__summary{color:var(--text-muted);margin-top:4px;font-style:italic}.grammar-body p,.grammar-body ul{line-height:1.6}.callout{background:var(--bg);border:1px solid var(--border);border-left:3px solid var(--accent);border-radius:6px;padding:10px 14px;font-size:14px}.grammar-example{background:var(--bg);border:1px solid var(--border);border-radius:6px;margin:12px 0;padding:12px 16px}.grammar-example__correct{color:var(--correct);margin:0 0 4px;font-weight:600}.grammar-example__incorrect{color:var(--wrong);margin:0 0 4px}.grammar-example__note{color:var(--text-muted);margin:4px 0 0;font-size:13px}.chip-row{flex-wrap:wrap;align-items:center;gap:6px;margin-top:16px;display:flex}.chip-row__label{color:var(--text-muted);margin-right:4px;font-size:13px}.chip{border:1px solid var(--border);background:var(--bg);color:var(--text);cursor:pointer;border-radius:999px;padding:3px 10px;font-size:12px;text-decoration:none;display:inline-block}.chip:hover{border-color:var(--accent);color:var(--accent)}.chip--link{border-color:var(--accent);color:var(--accent);font-weight:600}.quiz-controls{color:var(--text-muted);flex-wrap:wrap;align-items:center;gap:14px;margin-bottom:12px;font-size:13px;display:flex}.quiz-controls select{border:1px solid var(--border);background:var(--surface);color:var(--text);border-radius:6px;padding:4px 8px;font-size:13px}.quiz-controls__progress{color:var(--text);font-weight:600}.mcq-question{background:var(--surface);border:1px solid var(--border);border-radius:8px;max-width:560px;padding:20px 24px}.mcq-question__prompt{font-size:16px;font-weight:600}.mcq-question__choices{flex-direction:column;gap:8px;margin:0;padding:0;list-style:none;display:flex}.mcq-choice{text-align:left;border:1px solid var(--border);background:var(--bg);width:100%;color:var(--text);cursor:pointer;border-radius:6px;padding:10px 12px;font-size:14px}.mcq-choice:hover:not(:disabled){border-color:var(--accent)}.mcq-choice:disabled{cursor:default}.mcq-choice--correct{border-color:var(--correct);color:var(--correct);font-weight:600}.mcq-choice--wrong{border-color:var(--wrong);color:var(--wrong)}.mcq-question__feedback{border-top:1px solid var(--border);flex-direction:column;align-items:flex-start;gap:6px;margin-top:16px;padding-top:16px;display:flex}.fill-blank-form{gap:8px;margin-top:12px;display:flex}.fill-blank-input{border:1px solid var(--border);background:var(--bg);color:var(--text);border-radius:6px;flex:1;padding:8px 12px;font-size:14px}.score-summary{background:var(--surface);border:1px solid var(--border);border-radius:8px;max-width:480px;padding:24px}.score-summary__actions{flex-wrap:wrap;gap:10px;margin-top:12px;display:flex}.vocab-stats{color:var(--text-muted);margin:8px 0 12px;font-size:13px}.flashcard{max-width:480px}.flashcard__card{border:1px solid var(--border);background:var(--surface);width:100%;min-height:160px;color:var(--text);cursor:pointer;text-align:center;border-radius:10px;justify-content:center;align-items:center;padding:24px;font-size:18px;display:flex}.flashcard__front{font-weight:700}.flashcard__pos{color:var(--text-muted);margin-top:6px;font-size:13px;font-style:italic;font-weight:400}.flashcard__back p{margin:8px 0;font-size:15px}.flashcard__explanation{color:var(--text-muted);font-size:13px}.flashcard__controls{flex-wrap:wrap;align-items:center;gap:10px;margin-top:12px;display:flex}.flashcard__hint{color:var(--text-muted);margin-top:8px;font-size:13px}.checker-section{max-width:640px}.checker-disclaimer{background:var(--bg);border:1px solid var(--border);border-left:3px solid var(--accent);color:var(--text-muted);border-radius:6px;padding:10px 14px;font-size:13px}.checker-textarea{box-sizing:border-box;border:1px solid var(--border);background:var(--surface);width:100%;color:var(--text);font-size:15px;font-family:var(--sans);resize:vertical;border-radius:8px;padding:12px 14px}.checker-hint{color:var(--text-muted);font-style:italic}.checker-findings{flex-direction:column;gap:10px;margin:0;padding:0;list-style:none;display:flex}.checker-finding{background:var(--surface);border:1px solid var(--border);border-left:3px solid var(--wrong);border-radius:6px;padding:10px 14px}.checker-finding__category{color:var(--accent);text-transform:uppercase;letter-spacing:.04em;margin-bottom:4px;font-size:11px;font-weight:700;display:inline-block}.checker-finding__matched{font-family:var(--mono);background:var(--bg);border-radius:4px;margin:0 0 6px;padding:2px 6px;font-size:13px;display:inline-block}.checker-finding__message{margin:0 0 4px;font-size:14px}.checker-finding__suggestion{color:var(--correct);margin:0;font-size:14px}