:root{--sb: #2563eb;--sb-light: #dbeafe;--sb-dark: #1d4ed8;--purple: #7c3aed;--purple-light: #ede9fe;--green: #16a34a;--green-light: #dcfce7;--orange: #d97706;--red: #dc2626;--red-light: #fee2e2;--ink: #111827;--ink-2: #4b5563;--ink-3: #9ca3af;--line: #e5e7eb;--bg: #f7f8fa;--surface: #ffffff}*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif;color:var(--ink);background:var(--bg)}.layout{display:flex;height:100vh;width:100vw;overflow:hidden}.sidebar{width:240px;flex:none;background:var(--surface);border-right:1px solid var(--line);padding:20px 16px;display:flex;flex-direction:column;gap:20px;overflow-y:auto}.sidebar-brand{display:flex;align-items:center;gap:10px}.sidebar-logo{width:36px;height:36px;border-radius:9px;background:var(--sb);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700}.sidebar-title{font-weight:700;font-size:15px}.sidebar-subtitle{font-size:11px;color:var(--ink-3)}.sidebar-nav{display:flex;flex-direction:column;gap:2px}.navitem{display:block;width:100%;text-align:left;padding:9px 12px;border-radius:10px;border:none;background:none;font-size:14px;font-weight:500;color:var(--ink-2);cursor:pointer}.navitem:hover{background:#f3f4f6}.navitem.active{background:var(--sb-light);color:var(--sb-dark);font-weight:600}.sidebar-footer{margin-top:auto;display:flex;flex-direction:column;gap:10px}.sidebar-widget{padding:12px}.sidebar-widget-title{font-size:13px;font-weight:600;margin-bottom:6px}.sidebar-widget-text{font-size:12px;color:var(--ink-3);margin-bottom:6px}.main{flex:1;display:flex;flex-direction:column;overflow:hidden}.topbar{height:60px;flex:none;display:flex;align-items:center;padding:0 24px;border-bottom:1px solid var(--line);background:var(--surface)}.topbar-search{max-width:420px}.content{flex:1;overflow-y:auto;padding:24px}.card{background:var(--surface);border:1px solid var(--line);border-radius:14px;box-shadow:0 1px 2px #1018280a;padding:20px;margin-bottom:16px}.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;border-radius:10px;font-size:14px;font-weight:600;padding:9px 16px;cursor:pointer;border:1px solid transparent;background:#f3f4f6;color:var(--ink-2)}.btn-primary{background:var(--sb);color:#fff}.btn-primary:hover{background:var(--sb-dark)}.btn-secondary{background:var(--surface);color:var(--ink);border-color:var(--line)}.btn-danger{background:var(--surface);color:var(--red);border-color:var(--red-light)}.input{width:100%;padding:9px 12px;border:1px solid var(--line);border-radius:10px;font-size:14px;background:var(--surface);font-family:inherit}.input:focus{outline:2px solid var(--sb);outline-offset:0;border-color:var(--sb)}.input-error{border-color:var(--red)!important}.tag{display:inline-flex;align-items:center;font-size:12px;font-weight:600;padding:3px 10px;border-radius:999px}.tag-new{background:var(--sb-light);color:var(--sb-dark)}.tag-learning{background:#f3f4f6;color:var(--ink-2)}.tag-difficult{background:var(--red-light);color:var(--red)}.tag-pos{background:var(--purple-light);color:var(--purple)}.chip{display:inline-flex;align-items:center;padding:4px 12px;border-radius:999px;font-size:14px;font-weight:600}.chip-1{background:var(--sb-light);color:var(--sb-dark)}.chip-2{background:var(--green-light);color:var(--green)}.stat{padding:16px;border-radius:12px;border:1px solid var(--line);background:var(--surface)}.stat-label{font-size:13px;color:var(--ink-2)}.stat-value{font-size:26px;font-weight:700;margin-top:4px}.bar-track{width:100%;height:8px;border-radius:999px;background:#e5e7eb;overflow:hidden}.bar-fill{height:100%;border-radius:999px;background:var(--sb)}.seg{display:inline-flex;gap:4px;background:#f3f4f6;padding:3px;border-radius:10px}.seg-opt{padding:6px 14px;font-size:13px;font-weight:600;border-radius:8px;cursor:pointer;color:var(--ink-2);border:none;background:none}.seg-opt.checked{background:var(--surface);color:var(--ink);box-shadow:0 1px 2px #10182814}.table{width:100%;border-collapse:collapse}.table th{text-align:left;font-size:12px;color:var(--ink-2);font-weight:600;padding:10px 12px;border-bottom:1px solid var(--line)}.table td{padding:12px;border-bottom:1px solid var(--line);font-size:14px}.opt-btn{display:flex;align-items:center;padding:14px 18px;border-radius:12px;background:var(--surface);border:1px solid var(--line);cursor:pointer;font-size:16px;text-align:left}.opt-btn:hover{background:#f9fafb}.opt-btn.correct{background:var(--green-light);border-color:var(--green);color:#15803d}.opt-btn.incorrect{background:var(--red-light);border-color:var(--red);color:#b91c1c}.opt-btn.faded{opacity:.5}