.auth-screen{min-height:100vh;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,#1e1b4b 0,#6c63ff 100%);padding:20px}.auth-card{background:var(--bg-card);border-radius:var(--radius-lg);padding:40px;width:100%;max-width:420px;box-shadow:var(--shadow-lg);animation:.4s both fadeIn}.auth-logo{text-align:center;margin-bottom:28px}.auth-logo .logo-icon{font-size:3rem;display:block;margin-bottom:8px}.auth-logo h1{color:var(--primary)}.auth-logo p{color:var(--text-muted);font-size:14px}.app{display:flex;min-height:100vh}.sidebar{width:var(--sidebar-w);background:var(--bg-sidebar);display:flex;flex-direction:column;position:fixed;top:0;left:0;bottom:0;z-index:100;overflow-y:auto;transition:transform var(--transition)}.sidebar-logo{display:flex;align-items:center;gap:10px;padding:20px 16px 12px;border-bottom:1px solid rgba(255,255,255,.1)}.sidebar-logo .logo-icon{font-size:1.5rem}.sidebar-logo .logo-text{color:#fff;font-weight:700;font-size:1rem}.sidebar-user{display:flex;align-items:center;gap:10px;padding:16px;border-bottom:1px solid rgba(255,255,255,.1)}.user-avatar{width:36px;height:36px;border-radius:var(--radius-full);background:var(--primary);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px;flex-shrink:0}.user-info{display:flex;flex-direction:column;overflow:hidden}.user-info span{color:var(--text-on-sidebar);font-size:13px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.user-info span:first-child{font-weight:600;color:#fff}.nav-links{padding:12px 8px;flex:1}.nav-link{display:flex;align-items:center;gap:10px;padding:10px 12px;border-radius:var(--radius-sm);color:var(--text-on-sidebar);font-size:14px;font-weight:500;transition:background var(--transition),color var(--transition);margin-bottom:2px}.nav-link:hover{background:var(--bg-sidebar-hover);color:#fff}.nav-link.active{background:var(--primary);color:#fff}.nav-icon{font-size:1.1rem;width:20px;text-align:center}.sidebar-footer{padding:16px;border-top:1px solid rgba(255,255,255,.1)}.streak-widget{display:flex;align-items:center;gap:6px;color:var(--text-on-sidebar);font-size:13px;margin-bottom:10px}.streak-fire{font-size:1.2rem}.menu-toggle{display:none;position:fixed;top:12px;left:12px;z-index:200;background:var(--primary);color:#fff;border:none;border-radius:var(--radius-sm);width:40px;height:40px;font-size:1.2rem;align-items:center;justify-content:center;cursor:pointer}.menu-toggle:focus-visible{outline:#fff solid 3px;outline-offset:2px}.main-content{margin-left:var(--sidebar-w);flex:1;padding:28px;min-height:100vh}.page-header{margin-bottom:24px}.page-header h2{color:var(--text)}.page-header p{color:var(--text-muted);margin-top:4px}.grid-2{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.grid-4{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}.grid-auto{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:20px}.toast-container{position:fixed;bottom:24px;right:24px;z-index:9999;display:flex;flex-direction:column;gap:8px}.toast{background:var(--bg-card);border-left:4px solid var(--primary);border-radius:var(--radius-sm);padding:12px 16px;box-shadow:var(--shadow-lg);min-width:260px;max-width:340px;animation:.3s both fadeIn;font-size:14px}.toast.success{border-color:var(--success)}.toast.error{border-color:var(--danger)}.toast.warning{border-color:var(--warning)}.nav-section-label{font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:rgba(255,255,255,.4);padding:12px 20px 4px;margin-top:4px;pointer-events:none;border-top:1px solid rgba(255,255,255,.08)}@media (max-width:900px){.sidebar{transform:translateX(-100%)}.sidebar.open{transform:translateX(0)}.menu-toggle{display:flex}.main-content{margin-left:0;padding:64px 16px 16px}.grid-3,.grid-4{grid-template-columns:repeat(2,1fr)}.tab-group{flex-wrap:wrap}}@media (max-width:768px){.grid-4{grid-template-columns:repeat(2,1fr)}.page-header h2{font-size:1.3rem}td,th{padding:10px 12px;font-size:13px}.topic-mastery-name{width:130px}}@media (max-width:600px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}.auth-card{padding:24px}.main-content{padding:60px 12px 12px}.toast-container{bottom:12px;right:12px;left:12px}.toast{min-width:unset;max-width:100%}.topic-mastery-name{width:110px;font-size:12px}.tab-btn{font-size:12px;padding:7px 6px}}