:root{--navy: #1B3A5C;--navy-l: #D6EAF8;--blue: #2471A3;--orange: #CA6F1E;--orange-l: #FAE5D3;--green: #1E8449;--green-l: #D5F5E3;--red: #922B21;--red-l: #FADBD8;--gray-bg: #F4F6F9;--gray-d: #717D7E;--dark: #1C2833;--sidebar-w: 220px;--header-h: 56px;--radius: 10px;--radius-sm: 6px;--shadow: 0 1px 4px rgba(0,0,0,.08)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{font-size:16px;-webkit-text-size-adjust:100%}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif;background:var(--gray-bg);color:var(--dark);line-height:1.5;-webkit-font-smoothing:antialiased}.app-layout{display:flex;min-height:100vh}.app-sidebar{width:var(--sidebar-w);background:var(--navy);min-height:100vh;position:fixed;top:0;left:0;display:flex;flex-direction:column;z-index:100;transition:transform .25s ease}.app-main{margin-left:var(--sidebar-w);flex:1;min-width:0;display:flex;flex-direction:column}.app-header{height:var(--header-h);background:#fff;border-bottom:1px solid rgba(0,0,0,.07);display:flex;align-items:center;padding:0 1.5rem;gap:1rem;position:sticky;top:0;z-index:50}.app-content{flex:1;padding:1.5rem;max-width:960px;width:100%}.sidebar-brand{padding:1rem .875rem;border-bottom:1px solid rgba(255,255,255,.08);display:flex;align-items:center;gap:10px}.sidebar-brand-icon{width:34px;height:34px;background:var(--orange);border-radius:var(--radius-sm);display:flex;align-items:center;justify-content:center;font-size:18px;flex-shrink:0}.sidebar-brand-name{color:#fff;font-size:14px;font-weight:600;line-height:1.2}.sidebar-brand-sub{color:#fff6;font-size:11px}.sidebar-nav{flex:1;padding:.625rem .5rem;overflow-y:auto}.nav-item{display:flex;align-items:center;gap:10px;padding:9px 12px;border-radius:var(--radius-sm);margin-bottom:2px;background:transparent;border:none;width:100%;text-align:left;color:#ffffff8c;font-size:13.5px;cursor:pointer;transition:background .15s,color .15s;text-decoration:none}.nav-item:hover{background:#ffffff12;color:#ffffffd9}.nav-item.active{background:#ffffff21;color:#fff;font-weight:500}.nav-icon{font-size:16px;width:20px;text-align:center;flex-shrink:0}.nav-badge{margin-left:auto;background:var(--orange);color:#fff;font-size:10px;font-weight:600;padding:1px 6px;border-radius:10px}.sidebar-footer{padding:.875rem;border-top:1px solid rgba(255,255,255,.08)}.sidebar-user{display:flex;align-items:center;gap:10px;margin-bottom:8px}.sidebar-user-name{color:#fff;font-size:12px;font-weight:500;line-height:1.2}.sidebar-user-role{color:#fff6;font-size:10px}.card{background:#fff;border:1px solid rgba(0,0,0,.07);border-radius:var(--radius);box-shadow:var(--shadow)}.card-header{padding:1rem 1.25rem;border-bottom:1px solid rgba(0,0,0,.06);display:flex;align-items:center;justify-content:space-between}.card-header h3{font-size:14px;font-weight:600;color:var(--dark)}.card-body{padding:1.25rem}.stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:12px;margin-bottom:1.5rem}.stat-card{background:#fff;border:1px solid rgba(0,0,0,.07);border-radius:var(--radius);padding:1rem 1.125rem;box-shadow:var(--shadow)}.stat-label{font-size:11px;color:var(--gray-d);font-weight:500;text-transform:uppercase;letter-spacing:.5px;margin-bottom:6px;display:flex;align-items:center;gap:6px}.stat-value{font-size:26px;font-weight:700;color:var(--dark);line-height:1;margin-bottom:4px}.stat-sub{font-size:11px;color:var(--gray-d)}.avatar{border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:600;color:#fff;flex-shrink:0;font-size:13px}.progress-bar{background:#00000012;border-radius:10px;overflow:hidden}.progress-fill{height:100%;border-radius:10px;transition:width .4s ease}.tag{display:inline-flex;align-items:center;gap:4px;font-size:11px;font-weight:500;padding:2px 8px;border-radius:4px;line-height:1.6}.tag-gray{background:#f0f2f5;color:#5a6472}.tag-blue{background:var(--navy-l);color:var(--navy)}.tag-green{background:var(--green-l);color:#0f5132}.tag-orange{background:var(--orange-l);color:#7a3e0f}.tag-red{background:var(--red-l);color:var(--red)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:8px 16px;border-radius:var(--radius-sm);border:none;font-size:13px;font-weight:500;cursor:pointer;transition:opacity .15s,transform .1s;text-decoration:none;font-family:inherit;line-height:1;white-space:nowrap}.btn:disabled{opacity:.5;cursor:not-allowed}.btn:active:not(:disabled){transform:scale(.98)}.btn-primary{background:var(--navy);color:#fff}.btn-primary:hover:not(:disabled){background:#16324d}.btn-orange{background:var(--orange);color:#fff}.btn-orange:hover:not(:disabled){background:#b5621b}.btn-green{background:var(--green);color:#fff}.btn-green:hover:not(:disabled){background:#196b3a}.btn-ghost{background:transparent;color:var(--navy);border:1px solid rgba(0,0,0,.12)}.btn-ghost:hover:not(:disabled){background:var(--gray-bg)}.btn-danger{background:var(--red);color:#fff}.btn-sm{padding:5px 12px;font-size:12px}.btn-lg{padding:11px 22px;font-size:15px}.btn-full{width:100%}.form-group{margin-bottom:1.25rem}.form-label{display:block;font-size:12px;font-weight:500;color:var(--gray-d);margin-bottom:6px;text-transform:uppercase;letter-spacing:.4px}.form-input,.form-select,.form-textarea{width:100%;padding:9px 12px;border:1px solid rgba(0,0,0,.13);border-radius:var(--radius-sm);font-size:14px;color:var(--dark);background:#fff;transition:border-color .15s,box-shadow .15s;font-family:inherit}.form-input:focus,.form-select:focus,.form-textarea:focus{outline:none;border-color:var(--navy);box-shadow:0 0 0 3px #1b3a5c1a}.form-textarea{resize:vertical;min-height:100px;line-height:1.5}.page-title{font-size:18px;font-weight:700;color:var(--dark);margin:0 0 4px}.page-sub{font-size:13px;color:var(--gray-d);margin:0 0 1.5rem}.alert{padding:.875rem 1rem;border-radius:var(--radius);font-size:13px;border-left:4px solid;line-height:1.5}.alert-info{background:var(--navy-l);border-color:var(--navy);color:var(--navy)}.alert-success{background:var(--green-l);border-color:var(--green);color:#0f5132}.alert-warning{background:var(--orange-l);border-color:var(--orange);color:#7a3e0f}.alert-danger{background:var(--red-l);border-color:var(--red);color:var(--red)}.spinner{width:36px;height:36px;border:3px solid rgba(27,58,92,.15);border-top-color:var(--navy);border-radius:50%;animation:spin .7s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.loading-wrap{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:1rem;min-height:200px;color:var(--gray-d);font-size:14px}.empty-state{text-align:center;padding:3rem 1rem;color:var(--gray-d)}.empty-state-icon{font-size:3rem;margin-bottom:1rem;opacity:.5}.empty-state h3{font-size:16px;font-weight:600;color:var(--dark);margin-bottom:.5rem}.empty-state p{font-size:13px;margin-bottom:1.5rem}.tabs{display:flex;gap:4px;background:#0000000d;padding:4px;border-radius:var(--radius-sm);width:fit-content;margin-bottom:1.25rem}.tab-btn{padding:6px 14px;border-radius:4px;border:none;background:transparent;font-size:13px;font-weight:500;color:var(--gray-d);cursor:pointer;transition:background .15s,color .15s;font-family:inherit}.tab-btn.active{background:#fff;color:var(--navy);box-shadow:0 1px 3px #0000001a}.data-table{width:100%;border-collapse:collapse;font-size:13px}.data-table th{text-align:left;padding:10px 14px;font-size:11px;font-weight:600;text-transform:uppercase;letter-spacing:.5px;color:var(--gray-d);border-bottom:1px solid rgba(0,0,0,.07);background:var(--gray-bg)}.data-table td{padding:11px 14px;border-bottom:1px solid rgba(0,0,0,.05);vertical-align:middle}.data-table tr:last-child td{border-bottom:none}.data-table tr:hover td{background:var(--gray-bg)}.forum-post{background:#fff;border:1px solid rgba(0,0,0,.07);border-radius:var(--radius);padding:1rem 1.125rem;margin-bottom:8px;transition:box-shadow .15s;cursor:pointer}.forum-post:hover{box-shadow:0 2px 8px #0000001a}.forum-post.pinned{border-color:var(--orange);border-left-width:4px}.quiz-option{width:100%;text-align:left;padding:10px 14px;border:1.5px solid rgba(0,0,0,.1);border-radius:var(--radius-sm);background:#fff;cursor:pointer;font-size:13.5px;color:var(--dark);transition:border-color .15s,background .15s;font-family:inherit;line-height:1.45;margin-bottom:8px;display:block}.quiz-option:hover:not(:disabled){border-color:var(--navy);background:var(--navy-l)}.quiz-option.correct{border-color:var(--green);background:var(--green-l);color:#0f5132}.quiz-option.wrong{border-color:var(--red);background:var(--red-l);color:var(--red)}.quiz-option:disabled{cursor:default}.course-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem}.course-card{background:#fff;border:1px solid rgba(0,0,0,.07);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);transition:transform .2s,box-shadow .2s}.course-card:hover{transform:translateY(-2px);box-shadow:0 4px 16px #0000001a}.course-card-header{padding:1rem 1.125rem}.course-card-body{padding:.875rem 1.125rem 1.125rem}.live-card{background:#fff;border:1px solid rgba(0,0,0,.07);border-radius:var(--radius);padding:1rem 1.125rem;margin-bottom:10px;display:flex;align-items:flex-start;gap:12px;border-left-width:4px}.sidebar-toggle{display:none;background:none;border:none;cursor:pointer;padding:4px;color:var(--dark);font-size:20px}.sidebar-overlay{display:none;position:fixed;top:0;right:0;bottom:0;left:0;background:#00000073;z-index:90}@media (max-width: 768px){:root{--sidebar-w: 0px}.app-sidebar{transform:translate(-220px);width:220px}.app-sidebar.open{transform:translate(0)}.app-main{margin-left:0}.sidebar-toggle,.sidebar-overlay.open{display:block}.app-content{padding:1rem}.stat-grid{grid-template-columns:repeat(2,1fr)}.course-grid{grid-template-columns:1fr}.data-table th:nth-child(n+4),.data-table td:nth-child(n+4){display:none}}