:root{--background:#f7f8f6;--surface:#fff;--surface-muted:#f0f3ef;--surface-success:#edf8f0;--surface-danger:#fff4ef;--surface-strong:#1f2a23;--text:#1f2a23;--muted:#68746c;--line:#dfe5df;--accent:#1f7a5b;--accent-strong:#14553f;--warm:#c98742;--success:#22613a;--danger:#9b3d1f;--shadow:none;--radius-control:6px;--radius-panel:8px}*{box-sizing:border-box}html,body{min-height:100%;margin:0}body{background:var(--background);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}button,input,select{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.68}.app-shell{max-width:1040px;margin:0 auto;padding:28px 20px 48px}.hero{grid-template-columns:1fr auto;align-items:end;gap:28px;margin-bottom:28px;display:grid}.auth-hero,.learning-header{border-bottom:1px solid var(--line);grid-template-columns:1fr auto;align-items:center;gap:18px;margin-bottom:20px;padding-bottom:18px;display:grid}.learning-header.compact h1{margin-bottom:0;font-size:clamp(1.65rem,4vw,3rem);line-height:1.08}.header-actions{gap:10px;display:flex}.eyebrow{color:var(--accent);letter-spacing:0;text-transform:uppercase;margin:0 0 12px;font-size:.76rem;font-weight:800}h1,h2,p{margin-top:0}h1{max-width:780px;margin-bottom:14px;font-size:clamp(2rem,5vw,4rem);line-height:1.04}.auth-hero h1,.learning-header h1{max-width:760px}.intro{color:var(--muted);max-width:690px;margin-bottom:0;font-size:1rem;line-height:1.65}.stats{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);color:var(--text);align-content:center;min-width:150px;padding:18px}.stats strong{font-size:2.2rem;line-height:1;display:block}.stats span{color:var(--muted);margin-top:8px;line-height:1.4;display:block}.toolbar{border:1px solid var(--line);border-radius:var(--radius-panel);background:#ffffffc7;grid-template-columns:1fr 170px 210px;align-items:end;gap:16px;margin-bottom:18px;padding:16px;display:grid}label{gap:8px;display:grid}label span{color:var(--muted);font-size:.84rem;font-weight:700}input,select{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-control);color:var(--text);outline:none;width:100%;min-height:46px;padding:0 14px}input:focus,select:focus{border-color:var(--accent);box-shadow:0 0 0 3px #1f7a5b29}.learning-grid{grid-template-columns:minmax(0,1fr) 390px;align-items:start;gap:18px;display:grid}.flashcard,.word-list{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);box-shadow:var(--shadow)}.flashcard{min-height:520px;padding:34px}.card-topline{gap:10px;margin-bottom:42px;display:flex}.card-topline span,.word-row em{color:var(--accent-strong);background:#e8f2ec;border-radius:999px;padding:6px 10px;font-size:.8rem;font-style:normal;font-weight:800}.flashcard h2{overflow-wrap:anywhere;margin-bottom:14px;font-size:clamp(3rem,8vw,7rem);line-height:.95}.phonetic{color:var(--accent);margin-bottom:10px;font-size:1.08rem;font-weight:700}.part{color:var(--muted);margin-bottom:34px;font-weight:700}.primary-button,.card-actions button,.ghost-button,.known-button,.unknown-button,.auth-tabs button{border-radius:var(--radius-control);border:0;min-height:42px;padding:0 16px;font-weight:800;transition:background .16s,border-color .16s,color .16s,transform .16s}.primary-button{background:var(--accent);color:#fff}.primary-button:hover,.card-actions button:hover,.known-button:hover{background:var(--accent-strong);color:#fff}.full-width{width:100%}.ghost-button{background:var(--surface-muted);color:var(--text)}.ghost-button:hover,.unknown-button:hover{background:#dfe7df}.meaning{background:var(--surface-muted);border-left:3px solid var(--warm);border-radius:var(--radius-panel);margin-bottom:28px;padding:16px}.meaning strong{margin-bottom:0;font-size:1.45rem;display:block}.meaning p{margin-bottom:8px;font-size:1.2rem;line-height:1.6}.meaning small{color:var(--muted);font-size:1rem;line-height:1.5}.card-actions{justify-content:space-between;align-items:center;gap:12px;margin-top:36px;display:flex}.card-actions button{background:var(--surface-muted);color:var(--text)}.card-actions span{color:var(--muted);font-weight:800}.word-list{max-height:690px;overflow:hidden}.list-header{border-bottom:1px solid var(--line);justify-content:space-between;align-items:center;padding:18px;display:flex}.list-header h2{margin-bottom:0;font-size:1.1rem}.list-header span{color:var(--muted);font-size:.9rem;font-weight:700}.list-items{max-height:620px;display:grid;overflow:auto}.word-row{border:0;border-bottom:1px solid var(--line);color:var(--text);text-align:left;background:0 0;justify-content:space-between;align-items:center;gap:14px;min-height:76px;padding:14px 18px;display:flex}.word-row:hover,.word-row.active{background:#f1f7f3}.word-row span{gap:4px;display:grid}.word-row strong{font-size:1rem}.word-row small{color:var(--muted);font-size:.9rem}.empty-state{text-align:center;place-content:center;min-height:420px;display:grid}.empty-state h2{font-size:2rem}.empty-state p{color:var(--muted);margin-bottom:0}.auth-panel{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);max-width:520px;margin:0 auto;overflow:hidden}.auth-tabs{background:var(--surface-muted);grid-template-columns:1fr 1fr;padding:6px;display:grid}.auth-tabs button{color:var(--muted);background:0 0}.auth-tabs button.active{color:var(--text);background:#fff;box-shadow:0 1px #1f362714}.auth-form{gap:16px;padding:22px;display:grid}.error-message{background:var(--surface-danger);border-radius:var(--radius-control);color:var(--danger);border:1px solid #f0c5b5;margin:0;padding:12px 14px;font-weight:700;line-height:1.5}.progress-band{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);color:var(--text);grid-template-columns:repeat(4,1fr);gap:1px;margin-bottom:18px;display:grid;overflow:hidden}.progress-band div{border-right:1px solid var(--line);background:0 0;gap:5px;min-height:78px;padding:14px;display:grid}.progress-band div:last-child{border-right:0}.progress-band strong{font-size:1.55rem;line-height:1}.progress-band span{color:var(--muted);font-weight:700}.topic-home{gap:14px;display:grid}.topic-summary{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);grid-template-columns:1fr auto;align-items:center;gap:14px;padding:16px;display:grid}.topic-summary h2{margin-bottom:0;font-size:1.15rem}.summary-stats{flex-wrap:wrap;justify-content:end;gap:8px;display:flex}.summary-stats span{background:var(--surface-muted);color:var(--text);border-radius:999px;padding:8px 12px;font-size:.84rem;font-weight:800}.topic-grid{grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:10px;display:grid}.topic-loading{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);color:var(--muted);padding:24px;font-weight:800}.topic-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);color:var(--text);text-align:left;gap:12px;min-height:148px;padding:14px;transition:background .16s,border-color .16s,box-shadow .16s,transform .16s;display:grid}.topic-card:hover{border-color:var(--accent);background:#fbfcfb}.topic-card-head,.topic-card-foot{justify-content:space-between;align-items:start;gap:10px;display:flex}.topic-card strong{font-size:.98rem;line-height:1.25}.topic-card span,.topic-card small{color:var(--muted);font-weight:700}.topic-card em{color:var(--muted);font-size:.86rem;font-style:normal;font-weight:800}.topic-card-foot span{color:var(--accent)}.topic-meter-row{gap:5px;display:grid}.topic-meter{background:var(--surface-muted);border-radius:999px;height:6px;overflow:hidden}.topic-meter i{background:var(--warm);height:100%;display:block}.topic-meter.known i{background:var(--accent)}.feature-menu{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);gap:8px;margin-bottom:14px;padding:8px;display:flex}.feature-menu button{border-radius:var(--radius-control);color:var(--muted);white-space:nowrap;background:0 0;border:0;min-height:40px;padding:0 16px;font-weight:800}.feature-menu button.active,.feature-menu button:hover{background:var(--surface-muted);color:var(--text)}.study-layout{grid-template-columns:minmax(0,1fr) 340px;align-items:start;gap:14px;display:grid}.study-card,.practice-panel{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-panel);box-shadow:var(--shadow)}.study-card{min-height:440px;padding:28px}.quiz-card{position:relative}.quiz-card:before,.study-card:before{display:none}.study-card h2{overflow-wrap:anywhere;margin-bottom:14px;font-size:clamp(2.6rem,8vw,5.2rem);line-height:1}.decision-actions{grid-template-columns:1fr 1fr;gap:12px;margin-top:26px;display:grid}.quiz-prompt{color:var(--muted);margin-bottom:14px;font-size:1rem;font-weight:800}.review-mode-tabs{background:var(--surface-muted);border-radius:var(--radius-panel);grid-template-columns:repeat(4,1fr);gap:6px;margin-bottom:20px;padding:6px;display:grid}.review-mode-tabs button{border-radius:var(--radius-control);color:var(--muted);background:0 0;border:0;min-height:40px;padding:0 10px;font-size:.9rem;font-weight:850}.review-mode-tabs button.active,.review-mode-tabs button:hover{color:var(--text);background:#fff}.quiz-options{gap:12px;margin-top:22px;display:grid}.quiz-option{border:1px solid var(--line);border-radius:var(--radius-panel);color:var(--text);text-align:left;background:#f6f8f5;grid-template-columns:38px 1fr;align-items:center;gap:12px;min-height:64px;padding:12px 14px;line-height:1.45;transition:background .16s,border-color .16s,transform .16s;display:grid}.quiz-option:hover{border-color:var(--accent)}.quiz-option span{border:1px solid var(--line);background:#fff;border-radius:999px;justify-content:center;align-items:center;width:34px;height:34px;font-weight:900;display:inline-flex}.quiz-option.selected{border-color:var(--accent)}.quiz-option.correct{background:var(--surface-success);color:var(--success);border-color:#4fa66d}.quiz-option.wrong{background:var(--surface-danger);color:var(--danger);border-color:#df8b6a}.quiz-feedback{border-radius:var(--radius-control);margin:18px 0 0;padding:12px 14px;font-weight:800;line-height:1.5}.quiz-feedback.correct{background:var(--surface-success);color:var(--success);border:1px solid #4fa66d}.quiz-feedback.wrong{background:var(--surface-danger);color:var(--danger);border:1px solid #df8b6a}.typed-review,.self-check-review{gap:18px;display:grid}.typed-review>strong{border:1px solid var(--line);border-radius:var(--radius-panel);background:#f6f8f5;padding:20px;font-size:clamp(1.2rem,3vw,1.8rem);line-height:1.25;display:block}.typed-review label{margin-top:6px}.typed-review .primary-button{justify-self:start;min-width:150px}.compact-meaning{margin-bottom:0}.known-button{background:var(--accent);color:#fff}.unknown-button{background:var(--surface-muted);color:var(--text)}.practice-panel{gap:0;display:grid;overflow:hidden}.practice-panel section{border-bottom:1px solid var(--line);padding:16px}.practice-panel section:last-child{border-bottom:0}.practice-panel h2{margin-bottom:14px;font-size:1.1rem}.example-list,.tip-list{gap:10px;display:grid}.example-list p,.tip-list p{background:var(--surface-muted);border:1px solid var(--line);border-radius:var(--radius-control);margin:0;padding:12px;line-height:1.55}.example-list strong{color:var(--accent-strong);font-weight:900}@media (max-width:860px){.app-shell{padding:28px 14px 44px}.hero,.auth-hero,.learning-header,.toolbar,.learning-grid,.topic-summary,.study-layout{grid-template-columns:1fr}.header-actions,.summary-stats{justify-content:start}.progress-band{grid-template-columns:1fr 1fr}.feature-menu{grid-template-columns:1fr;display:grid}.review-mode-tabs{grid-template-columns:1fr 1fr}.stats{width:100%}.flashcard,.study-card{min-height:460px;padding:24px}.word-list{max-height:520px}}