:root{--primary:#3b6f81;--primary-dark:#2f5d6d;--background:#f7f8fa;--surface:#fff;--text:#1f2937;--text-muted:#6b7280;--border:#e5e7eb;--success:#4c9a67;--warning:#d9a441;--danger:#d96b6b;--accent:#e8f2f5;--shadow:0 8px 24px rgba(31,41,55,.055)}body{background:var(--background);color:var(--text)}.app-shell{padding-top:30px}.app-nav{min-height:62px;background:rgba(255,255,255,.96);border-bottom:1px solid var(--border)}.navbar-brand{font-size:17px;letter-spacing:-.015em}.brand-mark{width:29px;height:29px;border-radius:10px;background:var(--primary)}.app-nav .nav-link{border-radius:9px;color:var(--text-muted);font-size:.92rem;transition:background .16s ease,color .16s ease}.app-nav .nav-link:hover{background:#f2f6f7;color:var(--primary)}.app-nav .nav-link.nav-active{background:var(--accent);color:var(--primary);font-weight:700}.btn{border-radius:10px;box-shadow:none;transition:transform .16s ease,box-shadow .16s ease,background .16s ease}.btn:hover{transform:translateY(-1px)}.btn-primary{background:var(--primary);border-color:var(--primary);box-shadow:0 4px 10px rgba(59,111,129,.16)}.btn-primary:hover,.btn-primary:focus{background:var(--primary-dark);border-color:var(--primary-dark);box-shadow:0 6px 15px rgba(59,111,129,.2)}.btn-outline-primary{color:var(--primary);border-color:#bfd0d7;background:#fff}.btn-outline-primary:hover{background:var(--accent);border-color:#aac4cd;color:var(--primary)}.btn-outline-secondary{color:#5e6a75;border-color:#cfd7dc;background:#fff}.btn-outline-secondary:hover{background:#f3f5f6;color:#43515c}.card,.list-group-item,.form-card,.login-card,.empty-card,.next-lesson-card,.change-card,.lesson-row,.filter-card{border-color:var(--border);box-shadow:var(--shadow)}.form-control,.form-select{border-color:#dce1e6}.form-control:focus,.form-select:focus{border-color:#9fc2ce;box-shadow:0 0 0 .2rem rgba(59,111,129,.12)}.status-pill{font-size:.78rem;font-weight:700}.status-scheduled{background:#e8f2f5;color:#326777}.status-cancelled{background:#fff0f0;color:#b65353}.status-completed{background:#edf8f0;color:#3f8056}.page-kicker{margin:0 0 4px;color:var(--primary);font-size:.72rem;font-weight:800;letter-spacing:.1em;text-transform:uppercase}.page-heading h1{font-weight:720;letter-spacing:-.035em}.student-table-card{overflow:hidden;border:1px solid var(--border);border-radius:15px;background:var(--surface);box-shadow:var(--shadow)}.student-table-card .table{margin:0}.student-table-card thead th{padding:14px 16px;border-bottom:1px solid var(--border);background:#fbfcfd;color:#66727c;font-size:.73rem;font-weight:800;letter-spacing:.05em;text-transform:uppercase}.student-table-card tbody td{padding:15px 16px;border-color:#edf0f2;color:#47515c}.student-table-card tbody tr{transition:background .16s ease}.student-table-card tbody tr:hover{background:#f5fafb}.student-table-card tbody td:first-child{color:var(--text)}.lesson-count{display:inline-grid;place-items:center;min-width:27px;height:27px;padding:0 7px;border-radius:99px;background:#f0f4f5;color:#50606a;font-size:.8rem;font-weight:700}.student-status{display:inline-flex;align-items:center;gap:5px;padding:4px 9px;border-radius:99px;font-size:.76rem;font-weight:750}.student-status:before{content:'';width:6px;height:6px;border-radius:50%;background:currentColor}.student-active{background:#edf8f0;color:#3f8056}.student-inactive{background:#f3f4f6;color:#6b7280}.student-actions{display:flex;justify-content:flex-end;gap:6px;white-space:nowrap}.student-actions .btn{padding:.4rem .62rem;font-size:.79rem}.app-footer{color:#89929b}.app-footer .container{border-color:var(--border)}@media(max-width:767px){.student-actions{justify-content:flex-start}.student-table-card tbody td{padding:12px}.student-table-card thead th{padding:12px}.app-nav .nav-link.nav-active{padding-left:.6rem}}