*,:after,:before{box-sizing:border-box;margin:0;padding:0}:root{--ink:#0f172a;--ink-dim:#334155;--paper:#fff;--paper2:#f8fafc;--accent:#2563eb;--accent-hover:#1d4ed8;--accent-glow:rgba(37,99,235,.08);--accent-subtle:#eff6ff;--muted:#64748b;--card:#fff;--card-title:#0f172a;--card-border:#e2e8f0;--card-shadow:0 1px 3px rgba(15,23,42,.06),0 1px 2px rgba(15,23,42,.04);--card-shadow-hover:0 4px 16px rgba(15,23,42,.08),0 2px 4px rgba(15,23,42,.04);--border:#e2e8f0;--input-bg:#f8fafc;--success:#10b981;--success-glow:rgba(16,185,129,.08);--danger:#ef4444;--danger-glow:rgba(239,68,68,.06);--overlay:rgba(15,23,42,.4);--radius-sm:6px;--radius-md:8px;--radius-lg:12px;--sidebar-bg:#f1f5f9;--sidebar-border:#e2e8f0;--sidebar-hover:rgba(0,0,0,.04)}[data-theme=dark]{--ink:#f1f5f9;--ink-dim:#94a3b8;--paper:#0b1120;--paper2:#121b2e;--accent:#60a5fa;--accent-hover:#93bbfd;--accent-glow:rgba(96,165,250,.12);--accent-subtle:rgba(96,165,250,.08);--muted:#94a3b8;--card:#141f33;--card-title:#fff;--card-border:#1e2d48;--card-shadow:0 1px 3px rgba(0,0,0,.2);--card-shadow-hover:0 4px 16px rgba(0,0,0,.35);--border:#1e2d48;--input-bg:#141f33;--success:#34d399;--success-glow:rgba(52,211,153,.1);--danger:#ef4444;--danger-glow:rgba(239,68,68,.1);--overlay:rgba(0,0,0,.6);--sidebar-bg:#0a0f1c;--sidebar-border:#1e2d48;--sidebar-hover:hsla(0,0%,100%,.04)}body{font-family:var(--font-sans),"PingFang SC","Microsoft YaHei",sans-serif;background:var(--paper);color:var(--ink);min-height:100vh;transition:background .2s ease,color .2s ease}button,input,select,textarea{font-family:inherit}input:focus,select:focus,textarea:focus{outline:none}::-webkit-scrollbar{width:6px;height:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--border);border-radius:3px}::-webkit-scrollbar-thumb:hover{background:var(--muted)}::selection{background:var(--accent);color:#fff}@keyframes spin{to{transform:rotate(1turn)}}@keyframes fadeUp{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes shimmer{0%{background-position:-200% 0}to{background-position:200% 0}}@keyframes slideIn{0%{transform:translateX(-100%)}to{transform:translateX(0)}}@keyframes slideUp{0%{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}@keyframes pulse{0%,to{opacity:1}50%{opacity:.6}}.kcard-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));grid-gap:14px;gap:14px}@media (max-width:640px){.kcard-grid{grid-template-columns:1fr}}.kcard{transition:all .2s ease;cursor:pointer}.kcard:hover{transform:translateY(-2px);box-shadow:var(--card-shadow-hover);border-color:var(--accent)!important}.kcard:hover .kcard-bar{background:var(--accent)!important}.kcard:hover .kcard-hint{opacity:1!important}.opt-item:not(.answered):hover{background:var(--accent-glow)!important;border-color:var(--accent)!important}.skeleton{background:linear-gradient(90deg,var(--border) 0,var(--card) 40%,var(--border) 80%);background-size:200% 100%;animation:shimmer 1.5s ease-in-out infinite;border-radius:var(--radius-sm)}.toast-enter{animation:slideUp .3s ease both}.toast-exit{animation:fadeIn .2s ease reverse both}.back-to-top{position:fixed;bottom:24px;right:24px;z-index:200;width:40px;height:40px;border-radius:50%;border:1px solid var(--border);background:var(--card);color:var(--muted);cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:1rem;box-shadow:var(--card-shadow);transition:all .2s ease;animation:fadeUp .25s ease}.back-to-top:hover{border-color:var(--accent);color:var(--accent);box-shadow:var(--card-shadow-hover);transform:translateY(-2px)}@media (max-width:480px){.main-header{flex-wrap:wrap;gap:6px!important}.main-header h1{font-size:1rem!important}.header-badge{font-size:.5rem!important;padding:1px 6px!important}.main-content{padding:24px 14px 40px!important}.account-nav a,.account-nav button{font-size:.7rem!important;padding:4px 8px!important}}@media (max-width:640px){.sidebar-aside{width:100%!important;max-width:100%!important}}.recent-file-card{text-align:left;font:inherit;width:100%;padding:12px 14px;border-radius:var(--radius-md);background:var(--card);border:1px solid var(--card-border);cursor:pointer;transition:all .2s ease;display:flex;flex-direction:column;gap:4px}.recent-file-card:hover{border-color:var(--accent);box-shadow:var(--card-shadow-hover);transform:translateY(-1px)}