.navbar{background:var(--surface);border-bottom:1px solid var(--border);z-index:10;justify-content:space-between;align-items:center;height:72px;padding:0 20px;display:flex;position:sticky;top:0}.navbar-brand{align-items:center;line-height:0;display:flex}.navbar-right{align-items:center;gap:28px;display:flex}.navbar-links{align-items:center;gap:28px;display:none}.navbar-link{font-family:var(--font-body);color:var(--text-primary);font-size:16px;transition:color .12s}.navbar-link:hover{color:var(--primary)}.navbar-login{font-family:var(--font-body);border:1px solid var(--border);color:var(--text-primary);background:var(--surface);border-radius:8px;padding:6px 16px;font-size:14px;transition:border-color .12s}.navbar-login:hover{border-color:var(--text-primary)}.navbar-settings{position:relative}.navbar-gear{border:1px solid var(--border);background:var(--surface);width:34px;height:34px;color:var(--text-primary);border-radius:8px;justify-content:center;align-items:center;transition:border-color .12s,color .12s;display:flex}.navbar-gear:hover{border-color:var(--text-primary)}.navbar-dropdown{background:var(--surface);border:1px solid var(--border);z-index:100;border-radius:8px;min-width:140px;position:absolute;top:calc(100% + 8px);right:0;overflow:hidden;box-shadow:0 4px 16px #0003}.navbar-dropdown-item{text-align:left;width:100%;font-family:var(--font-body);color:var(--text-primary);background:0 0;padding:10px 16px;font-size:14px;transition:background .12s;display:block}.navbar-dropdown-item:hover{background:var(--surface-alt)}.navbar-confirm-overlay{z-index:200;background:#0009;justify-content:center;align-items:center;display:flex;position:fixed;inset:0}.navbar-confirm-modal{background:var(--surface);border:1px solid var(--border);border-radius:12px;flex-direction:column;gap:20px;width:100%;max-width:320px;padding:28px 24px 20px;display:flex}.navbar-confirm-text{font-family:var(--font-body);color:var(--text-primary);margin:0;font-size:15px}.navbar-confirm-actions{justify-content:flex-end;gap:10px;display:flex}.navbar-confirm-cancel{font-family:var(--font-body);border:1px solid var(--border);color:var(--text-primary);background:0 0;border-radius:8px;padding:7px 16px;font-size:14px;transition:border-color .12s}.navbar-confirm-cancel:hover{border-color:var(--text-primary)}.navbar-confirm-logout{font-family:var(--font-body);background:var(--error,#c0392b);color:#fff;border:none;border-radius:8px;padding:7px 16px;font-size:14px;transition:opacity .12s}.navbar-confirm-logout:hover{opacity:.85}@media (min-width:1024px){.navbar{height:auto;padding:14px 40px}.navbar-links{display:flex}.navbar-login{padding:6px 18px;font-size:15px}}
.chips-section{padding:22px 20px 0}.chips-header{flex-wrap:wrap;justify-content:space-between;align-items:flex-end;gap:12px;margin-bottom:14px;display:flex}.chips-header-top{flex:auto;min-width:0}.chips-heading{font-family:var(--font-display);margin:4px 0 0;font-size:20px;font-weight:700;line-height:1.2}.chip{font-family:var(--font-body);background:var(--surface);color:var(--text-secondary);border:1.5px solid var(--border);cursor:pointer;white-space:nowrap;border-radius:999px;padding:5px 13px;font-size:13px;font-weight:500;line-height:1.4;transition:border-color .1s,background .1s,color .1s}.chip:hover:not(.chip-active){border-color:var(--text-primary);color:var(--text-primary)}.chip-active{background:var(--text-primary);color:var(--surface);border-color:var(--text-primary)}.chips{flex-wrap:wrap;gap:8px;display:flex}.difficulty-chips{flex-shrink:0;align-items:center;gap:6px;display:flex}.difficulty-chip.chip-active.difficulty-chip-easy{background:var(--success,#3a9e6e);border-color:var(--success,#3a9e6e);color:#fff}.difficulty-chip.chip-active.difficulty-chip-medium{color:#fff;background:#d97706;border-color:#d97706}.difficulty-chip.chip-active.difficulty-chip-hard{background:var(--error,#e55);border-color:var(--error,#e55);color:#fff}.topic-grid{grid-template-columns:1fr 1fr;gap:10px;padding:14px 20px 24px;display:grid}.topic-card{background:var(--surface);border:1.5px solid var(--border);cursor:pointer;text-align:left;border-radius:12px;align-items:center;gap:12px;padding:14px;transition:border-color .1s,box-shadow .1s;display:flex}.topic-card:hover:not(:disabled){border-color:var(--primary,#5a7aff);box-shadow:var(--shadow-card)}.topic-card:disabled{opacity:.6;cursor:default}.topic-card-wide{grid-column:1/-1}.topic-icon{font-family:var(--font-mono);background:var(--surface-alt,#f5f5f5);border-radius:8px;flex-shrink:0;justify-content:center;align-items:center;width:36px;height:36px;font-size:18px;display:flex}.topic-card-body{flex:1;min-width:0}.topic-title{font-family:var(--font-display);font-size:14px;font-weight:600;line-height:1.2}.topic-sub{color:var(--text-secondary);margin-top:3px;font-size:11px}.topic-card-arrow{color:var(--text-secondary);flex-shrink:0;font-size:13px}.topic-card-arrow-desktop{display:none}@media (min-width:641px){.topic-card-arrow-desktop{display:inline}}
.landing{background:var(--surface)}.landing-error{background:var(--error-light,#2d1010);border:1px solid var(--error,#e55);color:var(--error,#e55);border-radius:8px;justify-content:space-between;align-items:center;gap:12px;margin:12px 20px 0;padding:10px 16px;font-size:14px;display:flex}.landing-error-close{cursor:pointer;color:inherit;background:0 0;border:none;flex-shrink:0;padding:0;font-size:16px;line-height:1}.hero-visual{display:none}.hero{border-bottom:1px dashed var(--border);padding:32px 20px 28px}.hero h1{font-family:var(--font-display);color:var(--text-primary);margin:0 0 12px;font-size:38px;font-weight:700;line-height:1.1}.hero-sub{font-family:var(--font-body);color:var(--text-secondary);margin:0 0 20px;font-size:16px}.hero-cta{padding:12px 28px;font-size:18px}@media (min-width:1024px){.landing.app-shell{border-left:none;border-right:none;max-width:none}.landing-content{width:100%;max-width:1200px;margin:0 auto}.hero{border-bottom:1px dashed var(--border);grid-template-columns:1fr 1fr;align-items:stretch;padding:0;display:grid}.hero-copy{flex-direction:column;justify-content:center;padding:56px 40px;display:flex}.hero h1{margin-bottom:16px;font-size:54px;line-height:1.05}.hero-sub{max-width:380px;margin-bottom:28px;font-size:20px}.hero-cta{padding:13px 30px;font-size:21px}.hero-visual{background:var(--surface-alt);border-left:1px solid var(--border);justify-content:center;align-items:center;min-height:300px;display:flex}.hero-visual-img{object-fit:contain;border-radius:12px;width:72%;height:auto}}