:root {
    --bg: #f0f2f5;
    --surface: #ffffff;
    --sidebar-bg: #0f172a;
    --sidebar-hover: #1e293b;
    --sidebar-active: #334155;
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --success: #16a34a;
    --danger: #dc2626;
    --warning: #f59e0b;
    --text: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --radius: 12px;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.08);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

.screen { display: none; }
.screen.active { display: flex; }
.hidden { display: none !important; }

/* ======================== LOGIN ======================== */
#login-screen {
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
}

.login-card {
    background: var(--surface);
    padding: 48px 40px;
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
    width: 400px;
    max-width: 90vw;
}

.login-logo {
    font-size: 32px;
    font-weight: 800;
    text-align: center;
    color: var(--sidebar-bg);
    letter-spacing: 2px;
    margin-bottom: 4px;
}

.login-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 32px;
    font-size: 14px;
}

/* ======================== FORMS ======================== */
.form-group { margin-bottom: 16px; }
.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 6px;
}
.form-group input, .form-group select, .form-group textarea {
    width: 100%;
    padding: 10px 14px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
    background: var(--surface);
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}
.form-group textarea { min-height: 80px; resize: vertical; }

.form-row { display: flex; gap: 12px; flex-wrap: wrap; }
.flex-1 { flex: 1; min-width: 0; }

.form-actions { display: flex; gap: 8px; margin-top: 8px; flex-wrap: wrap; }

.days-off-checkboxes { display: flex; gap: 12px; flex-wrap: wrap; }
.checkbox-label {
    display: inline-flex; align-items: center; gap: 4px;
    font-size: 14px; cursor: pointer; user-select: none;
}
.checkbox-label input[type="checkbox"] { width: 16px; height: 16px; cursor: pointer; }

/* ======================== BUTTONS ======================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
    text-decoration: none;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #15803d; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: #b91c1c; }
.btn-outline {
    background: transparent;
    color: var(--text);
    border: 1.5px solid var(--border);
}
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }
.btn-full { width: 100%; justify-content: center; }
.btn-sm { padding: 6px 12px; font-size: 12px; }

/* ======================== ALERTS ======================== */
.alert { padding: 12px 16px; border-radius: 8px; font-size: 14px; margin-top: 16px; }
.alert-error { background: #fef2f2; color: var(--danger); border: 1px solid #fecaca; }
.alert-success { background: #f0fdf4; color: var(--success); border: 1px solid #bbf7d0; }

/* ======================== SIDEBAR ======================== */
.sidebar {
    width: 260px;
    background: var(--sidebar-bg);
    color: #fff;
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    z-index: 100;
    transition: transform 0.3s;
}

.sidebar-brand {
    padding: 24px 24px 20px;
    font-size: 24px;
    font-weight: 800;
    letter-spacing: 2px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}

.sidebar-nav {
    flex: 1;
    padding: 12px 8px;
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 11px 16px;
    background: none;
    border: none;
    color: rgba(255,255,255,0.65);
    font-size: 14px;
    font-family: inherit;
    cursor: pointer;
    border-radius: 8px;
    transition: all 0.15s;
    margin-bottom: 2px;
}
.nav-item:hover { background: var(--sidebar-hover); color: #fff; }
.nav-item.active { background: var(--sidebar-active); color: #fff; font-weight: 600; }
.nav-icon { font-size: 18px; width: 24px; text-align: center; flex-shrink: 0; }
.nav-logout { margin: 8px; color: #f87171 !important; }
.nav-logout:hover { background: rgba(248,113,113,0.1) !important; }

/* ======================== MAIN CONTENT ======================== */
.main-content {
    margin-left: 260px;
    flex: 1;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.top-bar {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 20px 32px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 50;
}

.page-title { font-size: 22px; font-weight: 700; }
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text);
    padding: 4px 8px;
}

/* ======================== PAGES ======================== */
.page { display: none; padding: 32px; animation: fadeIn 0.2s; }
.page.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

/* ======================== STATS GRID ======================== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-bottom: 32px;
}

.stat-card {
    background: var(--surface);
    padding: 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.stat-label { font-size: 13px; color: var(--text-secondary); font-weight: 500; margin-bottom: 8px; }
.stat-value { font-size: 28px; font-weight: 800; color: var(--text); letter-spacing: -0.5px; }
.stat-card.revenue .stat-value { color: var(--success); }
.stat-card.danger .stat-value { color: var(--danger); }

/* ======================== QUICK ACTIONS ======================== */
.quick-actions { display: flex; gap: 12px; flex-wrap: wrap; }

/* ======================== SECTION HEADER ======================== */
.section-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; gap: 12px; flex-wrap: wrap; }
.section-header h2 { font-size: 18px; font-weight: 700; }

/* ======================== CARDS ======================== */
.card {
    background: var(--surface);
    padding: 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    margin-bottom: 16px;
}
.card h3 { font-size: 16px; font-weight: 700; margin-bottom: 16px; }

.cards-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 16px; }

/* ======================== INSTRUCTOR CARD ======================== */
.inst-card {
    background: var(--surface);
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 16px;
}
.inst-card .inst-info { flex: 1; min-width: 0; }
.inst-card .inst-info h3 { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.inst-card .inst-info p { font-size: 13px; color: var(--text-secondary); margin-bottom: 2px; word-wrap: break-word; }
.inst-card .inst-rating {
    font-size: 18px;
    font-weight: 700;
    color: var(--warning);
    white-space: nowrap;
    display: flex;
    align-items: center;
    gap: 4px;
    flex-shrink: 0;
}
.inst-card .inst-rating .star { color: #f59e0b; }
.inst-card .inst-actions { display: flex; gap: 6px; margin-top: 10px; flex-wrap: wrap; }

/* ======================== TABLES ======================== */
.table-wrapper { overflow-x: auto; -webkit-overflow-scrolling: touch; }
table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    overflow: hidden;
}
th {
    background: #f8fafc;
    padding: 12px 16px;
    text-align: left;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border);
}
td {
    padding: 12px 16px;
    font-size: 14px;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: #f8fafc; }

/* ======================== STATUS BADGES ======================== */
.badge {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    white-space: nowrap;
}
.badge-planned { background: #dbeafe; color: #1e40af; }
.badge-confirmed { background: #dcfce7; color: #166534; }
.badge-completed { background: #f0fdf4; color: #15803d; }
.badge-cancelled { background: #fef2f2; color: #991b1b; }
.badge-no_show { background: #fff7ed; color: #9a3412; }
.badge-primary { background: #dbeafe; color: #1e40af; }
.badge-success { background: #dcfce7; color: #166534; }
.badge-secondary { background: #f1f5f9; color: #475569; }
.badge-info { background: #e0f2fe; color: #0369a1; }

/* ======================== FILTERS ======================== */
.filters-bar {
    display: flex;
    gap: 12px;
    margin-bottom: 20px;
    flex-wrap: wrap;
    align-items: flex-end;
    background: var(--surface);
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.filter-group { display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.filter-group label { font-size: 12px; font-weight: 600; color: var(--text-secondary); }
.filter-group input, .filter-group select {
    padding: 8px 12px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    outline: none;
    min-width: 0;
}
.filter-group input:focus, .filter-group select:focus { border-color: var(--primary); }

/* ======================== ANALYTICS ======================== */
.analytics-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.heatmap { display: grid; grid-template-columns: repeat(7, 1fr); gap: 4px; margin-top: 12px; }
.heatmap-cell {
    aspect-ratio: 1;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 600;
    color: #fff;
    cursor: default;
}
.load-bar-container { margin-bottom: 12px; }
.load-bar-label { display: flex; justify-content: space-between; font-size: 13px; margin-bottom: 4px; }
.load-bar { height: 24px; background: #e2e8f0; border-radius: 6px; overflow: hidden; }
.load-bar-fill { height: 100%; background: var(--primary); border-radius: 6px; transition: width 0.5s; display: flex; align-items: center; padding-left: 8px; font-size: 12px; color: #fff; font-weight: 600; }

/* ======================== NOTIFICATIONS ======================== */
.notif-item {
    background: var(--surface);
    padding: 16px 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    margin-bottom: 12px;
    display: flex;
    gap: 12px;
    align-items: flex-start;
}
.notif-icon { font-size: 20px; flex-shrink: 0; margin-top: 2px; }
.notif-body { flex: 1; min-width: 0; }
.notif-body h4 { font-size: 14px; font-weight: 600; margin-bottom: 4px; }
.notif-body p { font-size: 13px; color: var(--text-secondary); }
.notif-low_rating { border-left: 4px solid var(--danger); }
.notif-red {
    background: #fff5f5;
    border: 1px solid var(--danger);
    box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.12);
}
.notif-red .notif-body h4 { color: var(--danger); }
.notif-new_booking { border-left: 4px solid var(--success); }

/* ======================== FAQ ======================== */
.faq-admin-item {
    background: var(--surface);
    padding: 16px 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    margin-bottom: 12px;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 16px;
}
.faq-admin-item > div { flex: 1; min-width: 0; }
.faq-admin-item h4 { font-size: 15px; font-weight: 600; margin-bottom: 4px; }
.faq-admin-item p { font-size: 13px; color: var(--text-secondary); word-wrap: break-word; }

/* ======================== TOAST ======================== */
.toast {
    position: fixed;
    bottom: 24px;
    right: 24px;
    padding: 14px 24px;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 600;
    color: #fff;
    z-index: 9999;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.3s;
}
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }
@keyframes slideUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }

.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }

/* ======================== MODAL ======================== */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 16px;
}
.modal-box {
    background: var(--surface);
    border-radius: 14px;
    width: 100%;
    max-width: 480px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
    animation: modalIn 0.15s ease-out;
}
@keyframes modalIn {
    from { transform: translateY(12px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}
.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 18px 20px;
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}
.modal-header h3 { margin: 0; font-size: 17px; font-weight: 700; }
.modal-close {
    background: none;
    border: none;
    font-size: 26px;
    line-height: 1;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0 4px;
    flex-shrink: 0;
}
.modal-close:hover { color: var(--text); }
.modal-body {
    padding: 20px;
    overflow-y: auto;
    flex: 1;
}
.modal-body .form-group { margin-bottom: 14px; }
.modal-body .form-group label { font-weight: 600; }
.modal-body .form-group input,
.modal-body .form-group select,
.modal-body .form-group textarea {
    width: 100%;
    padding: 10px 14px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    outline: none;
    background: var(--surface);
}
.modal-body .form-group input:focus,
.modal-body .form-group select:focus,
.modal-body .form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}
.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    padding: 16px 20px;
    border-top: 1px solid var(--border);
    flex-shrink: 0;
}

/* ======================== MOBILE CARDS ======================== */
.mobile-cards { display: none; }
.mobile-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 12px;
    box-shadow: var(--shadow);
}
.mobile-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 12px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
    gap: 8px;
}
.mobile-card-title {
    font-size: 15px;
    font-weight: 700;
    color: var(--text);
}
.mobile-card-row {
    display: flex;
    justify-content: space-between;
    padding: 6px 0;
    font-size: 13px;
    gap: 8px;
}
.mobile-card-label {
    color: var(--text-secondary);
    font-weight: 600;
    flex-shrink: 0;
}
.mobile-card-value {
    color: var(--text);
    text-align: right;
    word-break: break-word;
}

/* ======================== CLIENT CARDS ======================== */
#clients-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}
.client-card {
    background: var(--surface);
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.client-card h3 { font-size: 15px; font-weight: 700; margin-bottom: 8px; }
.client-card p { font-size: 13px; color: var(--text-secondary); margin-bottom: 4px; word-wrap: break-word; }
.client-card .client-actions { display: flex; gap: 6px; margin-top: 12px; flex-wrap: wrap; }

/* Client history expanded section */
.client-history-section {
    margin-top: 16px;
    padding: 16px;
    background: #f8fafc;
    border-radius: 10px;
    border: 1px solid var(--border);
}
.client-history-section h4 {
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
}
.client-history-event {
    padding: 12px 14px;
    margin-bottom: 10px;
    border-left: 3px solid var(--primary);
    background: white;
    border-radius: 0 8px 8px 0;
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.client-history-event:last-child { margin-bottom: 0; }

/* ======================== SUPPORT CHAT ======================== */
.support-layout { display: grid; grid-template-columns: 300px 1fr; gap: 16px; height: calc(100vh - 120px); }
.support-sidebar { background: var(--surface); border-radius: var(--radius); overflow-y: auto; padding: 12px; border: 1px solid var(--border); }
.support-sidebar h3 { margin: 0 0 12px 8px; font-size: 16px; }
.support-dialog-item { padding: 12px; border-radius: 8px; cursor: pointer; margin-bottom: 8px; background: var(--bg); border: 1px solid transparent; transition: all 0.2s; }
.support-dialog-item:hover { border-color: var(--primary); background: #f0f7ff; }
.support-dialog-item.has-new { border-color: var(--primary); background: rgba(37,99,235,0.06); }
.dialog-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 4px; }
.dialog-phone { font-size: 13px; color: var(--text-secondary); margin-bottom: 4px; }
.dialog-last-msg { font-size: 13px; color: var(--text-secondary); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.support-chat { background: var(--surface); border-radius: var(--radius); display: flex; flex-direction: column; overflow: hidden; border: 1px solid var(--border); }
.chat-empty { display: flex; align-items: center; justify-content: center; height: 100%; color: var(--text-secondary); min-height: 300px; }
.chat-active { display: flex; flex-direction: column; height: 100%; min-height: 400px; }
.chat-header { padding: 16px; border-bottom: 1px solid var(--border); }
.chat-header h3 { margin: 0 0 4px 0; font-size: 16px; }
.chat-messages { flex: 1; overflow-y: auto; padding: 16px; display: flex; flex-direction: column; gap: 10px; }
.chat-message { max-width: 70%; padding: 10px 14px; border-radius: 12px; word-wrap: break-word; }
.chat-message-user { align-self: flex-start; background: var(--bg); border: 1px solid var(--border); }
.chat-message-admin { align-self: flex-end; background: var(--primary); color: #fff; }
.chat-message-time { font-size: 11px; opacity: 0.6; margin-top: 4px; }
.chat-input-wrapper { padding: 12px 16px; border-top: 1px solid var(--border); display: flex; gap: 10px; align-items: flex-end; }
.chat-input-wrapper textarea { flex: 1; resize: none; padding: 8px 12px; border: 1.5px solid var(--border); border-radius: 8px; font-family: inherit; font-size: 14px; background: var(--surface); color: var(--text); outline: none; min-height: 40px; max-height: 120px; }
.chat-input-wrapper textarea:focus { border-color: var(--primary); }

/* ======================== CALENDAR ======================== */
.instructor-form-layout {
    display: flex;
    gap: 32px;
    margin-top: 20px;
}

.instructor-form-fields {
    flex: 1;
    min-width: 0;
}

.instructor-form-calendar {
    flex-shrink: 0;
    width: 470px;
}

.calendar-label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 12px;
}

.calendar-wrapper {
    display: flex;
    gap: 12px;
    align-items: flex-start;
}

.calendar-sidebar {
    min-width: 120px;
    flex-shrink: 0;
}

.calendar-sidebar h4 {
    font-size: 12px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text);
}

.calendar-months-list {
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.calendar-month-btn {
    padding: 5px 8px;
    background: white;
    border: 1px solid var(--border);
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 11px;
    font-weight: 500;
    color: var(--text);
    text-align: left;
}

.calendar-month-btn:hover {
    border-color: var(--primary);
    background: #f0f9ff;
}

.calendar-month-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
    font-weight: 600;
}

.calendar-main {
    flex: 1;
    background: white;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px;
    max-width: 300px;
}

.calendar-header {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 8px;
    padding-bottom: 6px;
    border-bottom: 1px solid var(--border);
}

.calendar-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--text);
}

.calendar-weekdays {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 2px;
    margin-bottom: 4px;
}

.calendar-weekday {
    text-align: center;
    font-size: 9px;
    font-weight: 700;
    color: var(--text-secondary);
    text-transform: uppercase;
    padding: 2px 0;
}

.calendar-days-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 3px;
}

.calendar-day-btn {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 500;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.15s;
    border: 1px solid transparent;
    background: white;
    color: var(--text);
    min-height: 28px;
}

.calendar-day-btn:hover:not(.past):not(.empty) {
    border-color: var(--primary);
    background: #eff6ff;
}

.calendar-day-btn.today {
    border-color: var(--primary);
    background: #eff6ff;
    color: var(--primary);
    font-weight: 700;
}

.calendar-day-btn.day-off {
    background: var(--danger);
    color: white;
    border-color: var(--danger);
    font-weight: 700;
}

.calendar-day-btn.day-off:hover {
    background: #b91c1c;
    border-color: #b91c1c;
}

.calendar-day-btn.past {
    opacity: 0.25;
    cursor: not-allowed;
    background: #f8f9fa;
    color: var(--text-secondary);
}

.calendar-day-btn.past:hover {
    border-color: transparent;
    background: #f8f9fa;
}

.calendar-day-btn.empty {
    cursor: default;
    background: transparent;
}

.calendar-legend {
    display: flex;
    gap: 12px;
    margin-top: 10px;
    padding-top: 8px;
    border-top: 1px solid var(--border);
    font-size: 10px;
}

.calendar-legend-item {
    display: flex;
    align-items: center;
    gap: 4px;
}

.calendar-legend-box {
    width: 14px;
    height: 14px;
    border-radius: 3px;
    flex-shrink: 0;
}

.calendar-legend-box.today {
    border: 1.5px solid var(--primary);
    background: #eff6ff;
}

.calendar-legend-box.day-off {
    background: var(--danger);
}

/* ======================== SLOT ITEMS ======================== */
#slots-panel {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    max-height: 420px;
    overflow-y: auto;
    overflow-x: hidden;
    padding-right: 4px;
}
.slot-item {
    padding: 12px;
    border: 2px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.slot-item:hover {
    border-color: var(--primary);
    transform: translateX(4px);
}

.slot-free {
    background: #f0fdf4;
    border-color: #86efac;
}

.slot-busy {
    background: #fef2f2;
    border-color: #fca5a5;
    opacity: 0.6;
    cursor: not-allowed;
}

.slot-busy:hover {
    transform: none;
}

/* Pending delete state */
tr.pending-delete td {
    background: #fef2f2 !important;
}
.pending-delete {
    border-color: var(--danger) !important;
    background: #fef2f2 !important;
}

/* ======================== RESPONSIVE ======================== */
@media (max-width: 992px) {
    .instructor-form-layout {
        flex-direction: column;
        gap: 24px;
    }
    
    .instructor-form-calendar {
        width: 100%;
    }
}

@media (max-width: 768px) {
    /* Sidebar */
    .sidebar { transform: translateX(-100%); width: 280px; }
    .sidebar.open { transform: translateX(0); }
    .main-content { margin-left: 0; }
    .mobile-menu-btn { display: block; }
    
    /* Top bar */
    .top-bar { padding: 14px 16px; gap: 12px; }
    .page-title { font-size: 18px; }
    
    /* Pages */
    .page { padding: 16px; }
    
    /* Stats */
    .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .stat-card { padding: 14px; }
    .stat-value { font-size: 20px; }
    .stat-label { font-size: 11px; }
    
    /* Analytics */
    .analytics-grid { grid-template-columns: 1fr; }
    
    /* Forms */
    .form-row { flex-direction: column; gap: 0; }
    .card { padding: 16px; }
    .card h3 { font-size: 15px; }
    
    /* Filters */
    .filters-bar { flex-direction: column; align-items: stretch; padding: 14px; gap: 10px; }
    .filter-group { width: 100%; }
    .filter-group input, .filter-group select { width: 100%; }
    
    /* Cards grid */
    .cards-grid { grid-template-columns: 1fr; }
    
    /* Instructor card */
    .inst-card { flex-direction: column; }
    .inst-card .inst-rating { align-self: flex-start; }
    
    /* Tables -> Mobile Cards */
    .table-wrapper table { display: none !important; }
    .mobile-cards { display: block; }
    
    /* Client cards */
    .client-card { padding: 14px; }
    
    /* Quick actions */
    .quick-actions { flex-direction: column; }
    
    /* Buttons */
    .btn { justify-content: center; }
    .section-header { flex-direction: column; align-items: stretch; gap: 10px; }
    .section-header h2 { font-size: 16px; }
    
    /* Login */
    .login-card { padding: 32px 24px; width: 100%; max-width: calc(100vw - 32px); }
    .login-logo { font-size: 28px; }
    
    /* Toast */
    .toast { right: 12px; left: 12px; bottom: 12px; text-align: center; }
    
    /* Modal */
    .modal-overlay { padding: 12px; align-items: flex-end; }
    .modal-box { max-width: 100%; max-height: 85vh; border-radius: 14px 14px 0 0; }
    .modal-body { padding: 16px; }
    .modal-body .form-group input,
    .modal-body .form-group select,
    .modal-body .form-group textarea { font-size: 16px; }
    .modal-footer { padding: 12px 16px; }
    
    /* Support */
    .support-layout { grid-template-columns: 1fr; height: auto; }
    .support-sidebar { height: 250px; }
    .support-chat { min-height: 400px; }
    .chat-message { max-width: 85%; }
    .chat-input-wrapper textarea { font-size: 16px; }
    
    /* FAQ */
    .faq-admin-item { flex-direction: column; gap: 12px; }
    .faq-admin-item > div { width: 100%; }
    
    /* Calendar */
    .calendar-wrapper { flex-direction: column; }
    .calendar-sidebar { min-width: 100%; }
    .calendar-months-list { flex-direction: row; overflow-x: auto; gap: 6px; padding-bottom: 8px; -webkit-overflow-scrolling: touch; }
    .calendar-month-btn { white-space: nowrap; }
    .calendar-main { max-width: 100%; }

    /* Manual booking form */
    #manual-booking-form > div { flex-direction: column !important; }
    #manual-booking-form > div > div { min-width: 100% !important; flex: auto !important; }
}

@media (max-width: 480px) {
    .stats-grid { grid-template-columns: 1fr; }
    .heatmap { gap: 2px; }
    .heatmap-cell { font-size: 9px; }
    .page { padding: 12px; }
    .form-group input, .form-group select, .form-group textarea { font-size: 16px; }
    .stat-card { padding: 12px; }
    .stat-value { font-size: 18px; }
}