:root {
    --background-color: #f7f9fc;
    --container-bg: #ffffff;
    --text-color: #1a2a44;
    --primary-color: #1e3a8a;
    --accent-color: #d4af37;
    --danger-color: #e63946;
    --success-color: #2ecc71;
    --secondary-bg: #e9ecef;
    --border-color: #e0e7ff;
    --shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    --spacing-unit: 24px;
}

[data-theme="dark"] {
    --background-color: #1a1a1a;
    --container-bg: #2c2c2c;
    --text-color: #e0e0e0;
    --primary-color: #3b82f6;
    --accent-color: #facc15;
    --danger-color: #ff6f61;
    --secondary-bg: #3a3a3a;
    --border-color: #444;
    --shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

body {
    background-color: var(--background-color);
    color: var(--text-color);
    padding: var(--spacing-unit);
    line-height: 1.6;
    font-size: 16px;
}

main.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--container-bg);
    border-radius: 16px;
    box-shadow: var(--shadow);
    overflow: hidden;
}

header.header {
    background: linear-gradient(90deg, var(--primary-color), #3b82f6);
    color: #fff;
    padding: var(--spacing-unit);
    font-size: 1.8em;
    font-weight: 600;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top-left-radius: 16px;
    border-top-right-radius: 16px;
    position: relative;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.header-logo i {
    font-size: 1.4em;
    color: var(--accent-color);
}

.header-actions {
    display: flex;
    gap: 10px;
    align-items: center;
}

.theme-toggle {
    border: none;
    border-radius: 8px;
    padding: 8px 12px;
    font-size: 0.9em;
    color: #fff;
    cursor: pointer;
    transition: background 0.3s, transform 0.3s ease, box-shadow 0.3s;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 6px;
    background: rgba(255, 255, 255, 0.15);
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: scale(1.05);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.user-menu {
    position: relative;
}

.menu-toggle {
    border: none;
    border-radius: 8px;
    padding: 8px 12px;
    font-size: 0.9em;
    color: #fff;
    cursor: pointer;
    transition: background 0.3s, transform 0.3s ease, box-shadow 0.3s;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 6px;
    background: rgba(255, 255, 255, 0.15);
}

.menu-toggle:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: scale(1.05);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.menu-dropdown {
    display: none;
    position: absolute;
    top: 100%;
    right: 0;
    background: var(--container-bg);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    min-width: 150px;
    z-index: 1000;
}

.menu-dropdown.active {
    display: block !important;
}

.menu-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 15px;
    color: var(--text-color);
    text-decoration: none;
    font-size: 0.9em;
    transition: background 0.3s;
}

.menu-item:hover {
    background: var(--secondary-bg);
}

.menu-item i {
    color: var(--primary-color);
}

nav.tabs {
    display: flex;
    flex-wrap: wrap;
    background: var(--secondary-bg);
    border-bottom: 1px solid var(--border-color);
    gap: 10px;
    padding: 10px;
}

.tab {
    flex: 1 1 150px;
    padding: 16px;
    text-align: center;
    background: var(--secondary-bg);
    border: none;
    cursor: pointer;
    font-size: 1.1em;
    font-weight: 500;
    color: var(--text-color);
    transition: background 0.3s, color 0.3s, transform 0.2s ease, box-shadow 0.3s;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
    border-radius: 8px;
    outline: none;
}

.tab i {
    color: var(--primary-color);
}

.tab:hover {
    background: #d1d5db;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.tab:focus {
    outline: 3px solid var(--accent-color);
    outline-offset: 2px;
}

.tab.active {
    background: var(--primary-color);
    color: #fff;
    transform: translateY(0);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.tab.active i {
    color: var(--accent-color);
}

.section {
    padding: var(--spacing-unit);
    display: none;
}

.section.active {
    display: block;
}

h2 {
    font-size: 1.6em;
    margin-bottom: var(--spacing-unit);
    color: var(--primary-color);
    font-weight: 600;
}

.form-group {
    margin-bottom: var(--spacing-unit);
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.form-group label {
    font-weight: 500;
    color: var(--text-color);
    font-size: 1em;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1em;
    background: var(--container-bg);
    color: var(--text-color);
    transition: border-color 0.3s, box-shadow 0.3s;
}

.form-group input[type="checkbox"] {
    width: auto;
}

.form-group .checkbox-group {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.form-group .checkbox-group label {
    display: flex;
    align-items: center;
    gap: 5px;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 8px rgba(30, 58, 138, 0.2);
}

.form-group .error {
    color: var(--danger-color);
    font-size: 0.9em;
    display: none;
}

.form-buttons {
    display: flex;
    gap: 20px;
    margin-top: var(--spacing-unit);
}

button {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 500;
    transition: background 0.3s, transform 0.2s ease, box-shadow 0.3s;
    display: flex;
    align-items: center;
    gap: 10px;
}

button:focus {
    outline: 3px solid var(--accent-color);
    outline-offset: 2px;
}

.btn-primary {
    background: var(--primary-color);
    color: #fff;
}

.btn-primary:hover {
    background: #1e40af;
    transform: scale(1.05);
}

.btn-secondary {
    background: #6b7280;
    color: #fff;
}

.btn-secondary:hover {
    background: #4b5563;
    transform: scale(1.05);
}

.btn-action {
    background: var(--primary-color);
    color: #fff;
    padding: 8px 16px;
    font-size: 0.9em;
    margin-right: 10px;
}

.btn-action:hover {
    background: #1e40af;
    transform: scale(1.05);
}

.btn-delete {
    background: var(--danger-color);
    color: #fff;
    padding: 8px 16px;
    font-size: 0.9em;
}

.btn-delete:hover {
    background: #dc2626;
    transform: scale(1.05);
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: var(--spacing-unit);
    background: var(--container-bg);
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    overflow: hidden;
}

th, td {
    padding: 16px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background: var(--primary-color);
    color: #fff;
    font-weight: 600;
}

td {
    font-size: 0.95em;
}

tr:hover {
    background-color: #f5f5f5;
}

[data-theme="dark"] tr:hover {
    background-color: #3a3a3a;
}

.toast {
    position: fixed;
    top: var(--spacing-unit);
    right: var(--spacing-unit);
    background: var(--success-color);
    color: #fff;
    padding: 16px 32px;
    border-radius: 10px;
    display: none;
    z-index: 1000;
    font-size: 1em;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 12px;
}

.toast.error {
    background: var(--danger-color);
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal-content {
    background: var(--container-bg);
    padding: var(--spacing-unit);
    border-radius: 12px;
    text-align: center;
    max-width: 400px;
    width: 90%;
    color: var(--text-color);
    box-shadow: var(--shadow);
}

.calendar {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 8px;
    margin-top: 16px;
    padding: 15px;
    background: var(--secondary-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
    width: 100%;
    overflow-x: auto;
}

.calendar div {
    padding: 10px;
    text-align: center;
    cursor: pointer;
    border-radius: 8px;
    font-size: 0.9em;
    min-width: 40px;
}

.calendar div.header {
    font-weight: 600;
    cursor: default;
    background: var(--primary-color);
    color: #fff;
}

.calendar div.booked {
    background: var(--danger-color);
    color: #fff;
    cursor: not-allowed;
}

.calendar div.available:hover {
    background: var(--primary-color);
    color: #fff;
}

.calendar-nav {
    display: flex;
    justify-content: space-between;
    margin-bottom: 15px;
    gap: 10px;
    align-items: center;
    flex-wrap: wrap;
}

.calendar-nav select {
    padding: 8px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: var(--container-bg);
    color: var(--text-color);
    flex: 1;
    min-width: 100px;
}

.calendar-nav button {
    padding: 8px 12px;
    font-size: 0.9em;
}

.pagination {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-top: var(--spacing-unit);
}

.pagination button {
    padding: 10px 15px;
    background: var(--primary-color);
    color: #fff;
    border-radius: 8px;
    transition: background 0.3s, transform 0.2s;
}

.pagination button:hover {
    background: #1e40af;
    transform: scale(1.05);
}

.pagination button.active {
    background: var(--accent-color);
    transform: scale(1);
}

.pagination button:disabled {
    background: #6b7280;
    cursor: not-allowed;
    transform: none;
}

.charts {
    display: flex;
    gap: var(--spacing-unit);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-unit);
}

.chart-container {
    flex: 1;
    min-width: 300px;
    max-width: 500px;
    background: var(--container-bg);
    padding: var(--spacing-unit);
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-align: center;
}

ul {
    list-style: none;
    padding: 0;
}

ul li {
    padding: 16px;
    border-bottom: 1px solid var(--border-color);
    background: var(--secondary-bg);
    border-radius: 10px;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
    transition: transform 0.2s ease, box-shadow 0.3s;
}

ul li:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.status-table {
    display: grid;
    grid-template-columns: minmax(120px, 1fr) repeat(auto-fit, minmax(35px, 1fr));
    gap: 6px;
    margin-top: 20px;
    align-items: center;
    overflow-x: auto;
}

.status-table div {
    padding: 10px;
    text-align: center;
    border: 1px solid var(--border-color);
    font-size: 0.9em;
    border-radius: 8px;
    transition: background 0.3s, transform 0.2s ease;
    min-width: 35px;
}

.status-table div.header {
    font-weight: 600;
    background: var(--primary-color);
    color: #fff;
}

.status-table div.booked {
    background: var(--danger-color);
    color: #fff;
}

.status-table div.available {
    background: var(--success-color);
    color: #fff;
}

.status-table div:hover {
    transform: scale(1.05);
}

.filter-bar {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
    background: var(--secondary-bg);
    padding: 15px;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.filter-bar select {
    flex: 1;
    min-width: 140px;
    max-width: 180px;
}

.search-bar {
    margin-bottom: 20px;
}

.search-bar input {
    width: 100%;
    max-width: 400px;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1em;
    transition: border-color 0.3s;
}

.search-bar input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 8px rgba(30, 58, 138, 0.2);
}

.action-buttons {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.action-buttons button {
    padding: 12px 20px;
    font-size: 1em;
    transition: transform 0.2s, background 0.3s;
}

.action-buttons .btn-primary {
    background: #2196F3;
}

.action-buttons .btn-primary:hover {
    background: #1976D2;
}

.action-buttons .btn-clear {
    background: #f44336;
    color: #fff;
}

.action-buttons .btn-clear:hover {
    background: #d32f2f;
}

.reminder-list {
    margin-bottom: 25px;
    padding: 15px;
    background: var(--secondary-bg);
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.reminder-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 15px;
    background: var(--container-bg);
    border-radius: 8px;
    margin-bottom: 10px;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.05);
}

.reminder-item span {
    font-size: 0.95em;
}

.reminder-item .btn-action {
    padding: 6px 12px;
    font-size: 0.9em;
    background: var(--success-color);
}

.reminder-item .btn-action:hover {
    background: #27ae60;
}

.mobile-card {
    display: block;
    padding: 20px;
    margin-bottom: 20px;
    background: var(--container-bg);
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.mobile-card p {
    margin-bottom: 10px;
    font-size: 0.95em;
}

.mobile-card button {
    margin-right: 10px;
    margin-top: 10px;
}

@media (max-width: 600px) {
    .tabs {
        flex-direction: column;
        gap: 8px;
    }

    .tab {
        flex: 1 1 100%;
    }

    table {
        display: none;
    }

    .mobile-card {
        display: block;
    }

    .filter-bar {
        flex-direction: column;
    }

    .filter-bar select {
        max-width: 100%;
    }

    .checkbox-group {
        flex-direction: column;
    }

    .action-buttons {
        flex-direction: column;
        gap: 10px;
    }

    .action-buttons button {
        width: 100%;
    }

    .header-actions {
        gap: 8px;
    }

    .theme-toggle, .menu-toggle {
        padding: 6px 10px;
        font-size: 0.85em;
    }

    .calendar {
        grid-template-columns: repeat(7, 1fr);
        gap: 4px;
        padding: 8px;
        font-size: 0.75em;
    }

    .calendar div {
        padding: 6px;
        font-size: 0.75em;
        min-width: 30px;
    }

    .calendar div.header {
        font-size: 0.7em;
        padding: 4px;
    }

    .calendar-nav {
        flex-direction: column;
        gap: 6px;
    }

    .calendar-nav select, .calendar-nav button {
        width: 100%;
        max-width: 180px;
        font-size: 0.85em;
        padding: 6px;
    }

    .status-table {
        grid-template-columns: minmax(80px, 1fr) repeat(auto-fit, minmax(25px, 1fr));
        gap: 3px;
    }

    .status-table div {
        padding: 6px;
        font-size: 0.75em;
        min-width: 25px;
    }

    .menu-dropdown {
        min-width: 120px;
        top: 40px;
        right: 0;
    }
}

.login-container, .register-container {
    max-width: 400px;
    margin: 50px auto;
    padding: 30px;
    background: var(--container-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-align: center;
}

.login-container h2, .register-container h2 {
    margin-bottom: 20px;
    color: var(--primary-color);
}

.login-form .form-group, .register-form .form-group {
    margin-bottom: 20px;
    text-align: left;
}

.login-form label, .register-form label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

.login-form input, .register-form input {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1em;
}

.login-form input:focus, .register-form input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 8px rgba(30, 58, 138, 0.2);
}

.login-form .error, .register-form .error {
    color: var(--danger-color);
    font-size: 0.9em;
    margin-top: 10px;
    display: block;
}

.login-form .message, .register-form .message {
    color: var(--success-color);
    font-size: 0.9em;
    margin-top: 10px;
    display: block;
}

.login-form button, .register-form button {
    width: 100%;
    padding: 12px;
    background: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
}

.login-form button:hover, .register-form button:hover {
    background: #1e40af;
    transform: scale(1.05);
}

.register-link, .login-link {
    margin-top: 15px;
    display: block;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 0.9em;
}

.register-link:hover, .login-link:hover {
    text-decoration: underline;
}