:root{--teal:#0f8b8d;--teal-dark:#0a6567;--yellow:#ffc93c;--pink:#ff6b9d;--bg:#f7faf9;--text:#1f2d2d;--card-bg:#fff;--border:#e2e8e8}*{box-sizing:border-box}body{margin:0;font-family:Segoe UI,Tahoma,sans-serif;background:var(--bg);color:var(--text)}a{color:inherit;text-decoration:none}.auth-page{min-height:100vh;display:flex;align-items:center;justify-content:center}.auth-card{background:var(--card-bg);padding:2.5rem;border-radius:16px;box-shadow:0 8px 24px rgba(0,0,0,.08);width:100%;max-width:380px;display:flex;flex-direction:column;gap:1rem}.auth-card h1{margin:0 0 .5rem;font-size:1.4rem;color:var(--teal-dark)}.auth-card label{display:flex;flex-direction:column;gap:.35rem;font-size:.9rem}.auth-card input{padding:.6rem .75rem;border:1px solid var(--border);border-radius:8px;font-size:1rem}.auth-card button{margin-top:.5rem;padding:.7rem;border:none;border-radius:8px;background:var(--teal);color:#fff;font-size:1rem;cursor:pointer}.auth-card button:disabled{opacity:.6;cursor:not-allowed}.error-text{color:#c0392b;font-size:.9rem}.course-detail-page,.dashboard-page,.lesson-player-page{max-width:960px;margin:0 auto;padding:2rem 1.5rem}.dashboard-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:1.5rem}.dashboard-header button{padding:.5rem 1rem;border:1px solid var(--border);border-radius:8px;background:#fff;cursor:pointer}.course-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));grid-gap:1.25rem;gap:1.25rem}.course-card{background:var(--card-bg);border-radius:14px;padding:1rem;box-shadow:0 4px 12px rgba(0,0,0,.06);display:block}.course-thumb img{object-fit:cover}.course-thumb img,.course-thumb-placeholder{width:100%;border-radius:10px;aspect-ratio:16/9}.course-thumb-placeholder{background:var(--yellow);display:flex;align-items:center;justify-content:center;font-size:2rem;color:#fff}.course-level{color:var(--teal-dark);font-size:.85rem;margin:.25rem 0}.progress-bar{background:var(--border);border-radius:999px;height:8px;overflow:hidden;margin-top:.5rem}.progress-fill{background:var(--pink);height:100%}.progress-label{font-size:.8rem;margin:.35rem 0 0}.back-link{display:inline-block;margin-bottom:1rem;color:var(--teal-dark);font-size:.9rem}.lesson-list{list-style:none;padding:0;display:flex;flex-direction:column;gap:.6rem}.lesson-item{background:var(--card-bg);border-radius:10px;padding:.9rem 1.1rem;box-shadow:0 2px 8px rgba(0,0,0,.05)}.lesson-item.locked{opacity:.6}.lesson-order{font-weight:600;margin-right:.4rem}.preview-badge{margin-left:.5rem;font-size:.75rem;background:var(--yellow);color:#fff;padding:.1rem .5rem;border-radius:999px}.lock-icon{margin-left:.5rem;font-size:.85rem;color:#888}.device-conflict-banner,.locked-banner{background:#fff4e5;border:1px solid #ffc93c;border-radius:10px;padding:1rem;margin-bottom:1rem}.device-conflict-banner button{margin-top:.5rem;padding:.5rem 1rem;border:none;border-radius:8px;background:var(--pink);color:#fff;cursor:pointer}.video-wrapper{position:relative;width:100%;aspect-ratio:16/9;border-radius:12px;overflow:hidden;background:#000}.video-wrapper iframe{width:100%;height:100%;border:none}.materials-section{margin-top:1.5rem}.materials-section ul{list-style:none;padding:0}.materials-section li{padding:.5rem 0}.btn-link{background:none;border:none;color:var(--teal-dark);cursor:pointer;font-size:.85rem;padding:0;text-align:left}.admin-shell{display:flex;min-height:100vh}.admin-sidebar{width:220px;background:var(--teal-dark);color:#fff;display:flex;flex-direction:column;flex-shrink:0}.admin-sidebar-brand{padding:1.25rem 1.25rem 1rem;font-weight:700;font-size:1.05rem;border-bottom:1px solid hsla(0,0%,100%,.15)}.admin-nav{display:flex;flex-direction:column;padding:.75rem 0}.admin-nav-link{padding:.7rem 1.25rem;color:hsla(0,0%,100%,.85);font-size:.92rem}.admin-nav-link:hover{background:hsla(0,0%,100%,.08)}.admin-nav-link.active{background:hsla(0,0%,100%,.16);color:#fff;font-weight:600;border-right:3px solid var(--yellow)}.admin-main{flex:1 1;display:flex;flex-direction:column;min-width:0}.admin-topbar{display:flex;justify-content:space-between;align-items:center;padding:1rem 1.75rem;background:#fff;border-bottom:1px solid var(--border)}.admin-topbar button{padding:.45rem .9rem;border:1px solid var(--border);border-radius:8px;background:#fff;cursor:pointer}.badge{display:inline-block;background:var(--yellow);color:#fff;font-size:.7rem;padding:.15rem .5rem;border-radius:999px;margin-left:.4rem;vertical-align:middle}.admin-content{padding:1.75rem;max-width:1100px}.admin-page-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:1.25rem}.admin-page-header h1{font-size:1.3rem;margin:0;color:var(--teal-dark)}.btn-primary{padding:.55rem 1rem;border:none;border-radius:8px;background:var(--teal);color:#fff;font-size:.9rem;cursor:pointer}.btn-primary:disabled{opacity:.6;cursor:not-allowed}.btn-secondary{border:1px solid var(--border);border-radius:8px;background:#fff}.btn-danger,.btn-secondary{padding:.5rem .9rem;font-size:.85rem;cursor:pointer}.btn-danger{border:1px solid #e0a0a0;border-radius:8px;background:#fdf0f0;color:#c0392b}.stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));grid-gap:1rem;gap:1rem;margin-bottom:2rem}.stat-card{background:var(--card-bg);border-radius:12px;padding:1.1rem 1.25rem;box-shadow:0 2px 8px rgba(0,0,0,.05)}.stat-card .stat-value{font-size:1.6rem;font-weight:700;color:var(--teal-dark)}.stat-card .stat-label{font-size:.82rem;color:#667;margin-top:.2rem}.admin-section{margin-bottom:2rem}.admin-section h2{font-size:1.05rem;margin-bottom:.75rem;color:var(--teal-dark)}.data-table{width:100%;border-collapse:collapse;background:var(--card-bg);border-radius:12px;overflow:hidden;box-shadow:0 2px 8px rgba(0,0,0,.05)}.data-table td,.data-table th{text-align:left;padding:.65rem .9rem;font-size:.88rem;border-bottom:1px solid var(--border)}.data-table th{background:var(--bg);color:var(--teal-dark);font-weight:600}.data-table tr:last-child td{border-bottom:none}.status-pill{display:inline-block;padding:.15rem .6rem;border-radius:999px;font-size:.75rem;font-weight:600}.status-pill.active,.status-pill.paid,.status-pill.published{background:#e2f6ea;color:#1a8a4a}.status-pill.draft,.status-pill.pending{background:#fff4e0;color:#b8790a}.status-pill.archived,.status-pill.cancelled,.status-pill.expired,.status-pill.failed,.status-pill.suspended{background:#fdeaea;color:#c0392b}.status-pill.refunded{background:#eee;color:#555}.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.4);display:flex;align-items:center;justify-content:center;z-index:50;padding:1rem}.modal-card{background:#fff;border-radius:14px;padding:1.75rem;width:100%;max-width:480px;max-height:90vh;overflow-y:auto;display:flex;flex-direction:column;gap:.9rem}.modal-card h2{margin:0;font-size:1.15rem;color:var(--teal-dark)}.form-field{display:flex;flex-direction:column;gap:.35rem;font-size:.88rem}.form-field input,.form-field select,.form-field textarea{padding:.55rem .7rem;border:1px solid var(--border);border-radius:8px;font-size:.92rem;font-family:inherit}.form-row{display:flex;gap:.75rem}.form-row .form-field{flex:1 1}.modal-actions{display:flex;justify-content:flex-end;gap:.6rem;margin-top:.4rem}.action-row{display:flex;gap:.5rem;flex-wrap:wrap}.empty-state{color:#778;font-size:.9rem;padding:1.5rem 0;text-align:center}.help-text{font-size:.8rem;color:#778;margin:0}.copy-box{background:var(--bg);border:1px solid var(--border);border-radius:8px;padding:.6rem .75rem;font-family:monospace;font-size:.8rem;word-break:break-all;-webkit-user-select:all;-moz-user-select:all;user-select:all}