@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

/* ── Design Tokens ── */
:root {
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Brand / semantic (same in both modes) */
    --color-primary: #007AFF;
    --color-primary-dark: #0056CC;
    --color-success: #34C759;
    --color-warning: #FF9500;
    --color-error: #FF3B30;

    /* Status badge backgrounds */
    --color-active-bg: #d4f4de;
    --color-active-text: #155724;
    --color-maintenance-bg: #fff3cd;
    --color-maintenance-text: #856404;
    --color-offline-bg: #fde8e8;
    --color-offline-text: #721c24;

    /* Light mode defaults */
    --color-bg: #F2F2F7;
    --color-surface: #FFFFFF;
    --color-card: #F8F8FA;
    --color-border: #E5E5EA;
    --color-text: #1C1C1E;
    --color-text-secondary: #6E6E73;
    --color-text-tertiary: #8E8E93;
    --color-header-bg: #1C1C1E;
    --color-header-text: #FFFFFF;
    --color-nav-bg: #FFFFFF;
    --color-input-bg: #FFFFFF;
    --color-modal-bg: #FFFFFF;
    --color-table-head-bg: #F8F8FA;
    --color-row-hover: rgba(0, 122, 255, 0.05);
    --color-overlay: rgba(0,0,0,0.4);

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --shadow-sm: 0 1px 4px rgba(0,0,0,0.08);
    --shadow-md: 0 2px 10px rgba(0,0,0,0.10);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.15);
}

[data-theme="dark"] {
    --color-bg: #000000;
    --color-surface: #1C1C1E;
    --color-card: #2C2C2E;
    --color-border: #3A3A3C;
    --color-text: #FFFFFF;
    --color-text-secondary: #8E8E93;
    --color-text-tertiary: #636366;
    --color-header-bg: #000000;
    --color-header-text: #FFFFFF;
    --color-nav-bg: #1C1C1E;
    --color-input-bg: #2C2C2E;
    --color-modal-bg: #1C1C1E;
    --color-table-head-bg: #2C2C2E;
    --color-row-hover: rgba(255,255,255,0.05);
    --color-overlay: rgba(0,0,0,0.6);

    --color-active-bg: rgba(52,199,89,0.15);
    --color-active-text: #34C759;
    --color-maintenance-bg: rgba(255,149,0,0.15);
    --color-maintenance-text: #FF9500;
    --color-offline-bg: rgba(255,59,48,0.15);
    --color-offline-text: #FF3B30;

    --shadow-sm: 0 1px 4px rgba(0,0,0,0.3);
    --shadow-md: 0 2px 10px rgba(0,0,0,0.4);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.5);
}

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

body {
    font-family: var(--font);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    transition: background-color 0.2s, color 0.2s;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ── Header ── */
.header {
    background: var(--color-header-bg);
    color: var(--color-header-text);
    padding: 1rem 0;
    box-shadow: var(--shadow-md);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-header-text);
}

.logo i {
    margin-right: 0.5rem;
    color: var(--color-primary);
}

.logo-img {
    height: 36px;
    width: auto;
    display: block;
}

.stat-card-clickable {
    cursor: pointer;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.btn-logout {
    background: rgba(255,255,255,0.15);
    color: var(--color-header-text);
    border: 1px solid rgba(255,255,255,0.2);
    padding: 0.4rem 0.9rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-family: var(--font);
    font-size: 0.875rem;
    font-weight: 500;
    transition: background 0.2s;
}

.btn-logout:hover {
    background: rgba(255,255,255,0.25);
}

/* Theme toggle button */
.btn-theme-toggle {
    background: rgba(255,255,255,0.12);
    color: var(--color-header-text);
    border: 1px solid rgba(255,255,255,0.2);
    padding: 0.4rem 0.7rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    transition: background 0.2s;
}

.btn-theme-toggle:hover {
    background: rgba(255,255,255,0.22);
}

/* ── Navigation ── */
.nav {
    background: var(--color-nav-bg);
    border-bottom: 1px solid var(--color-border);
    padding: 0;
    transition: background-color 0.2s;
}

.nav-menu {
    display: flex;
    list-style: none;
}

.nav-link {
    display: block;
    padding: 1rem 1.5rem;
    text-decoration: none;
    color: var(--color-text-secondary);
    font-weight: 500;
    font-size: 0.9375rem;
    transition: all 0.2s;
    border-bottom: 3px solid transparent;
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
    background: rgba(0, 122, 255, 0.07);
    border-bottom-color: var(--color-primary);
}

.nav-link i {
    margin-right: 0.5rem;
}

/* ── Main content ── */
.main {
    padding: 2rem 0;
    min-height: calc(100vh - 120px);
}

.section {
    display: none;
}

.section.active {
    display: block;
}

.section h2 {
    color: var(--color-text);
    margin-bottom: 1.5rem;
    font-size: 1.75rem;
    font-weight: 700;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

/* ── Dashboard stats ── */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.25rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--color-surface);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    display: flex;
    align-items: center;
    border: 1px solid var(--color-border);
    transition: transform 0.2s, box-shadow 0.2s, background-color 0.2s;
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.stat-icon {
    background: var(--color-primary);
    color: white;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 1rem;
    font-size: 1.4rem;
    flex-shrink: 0;
}

.stat-info h3 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 0.2rem;
    line-height: 1;
}

.stat-info p {
    color: var(--color-text-secondary);
    font-weight: 500;
    font-size: 0.875rem;
}

/* ── Data tables ── */
.data-table {
    background: var(--color-surface);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: background-color 0.2s;
}

table {
    width: 100%;
    border-collapse: collapse;
}

thead {
    background: var(--color-table-head-bg);
}

th, td {
    padding: 0.875rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
    font-size: 0.9375rem;
}

th {
    font-weight: 600;
    color: var(--color-text);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

td {
    color: var(--color-text);
}

tr:hover {
    background: var(--color-row-hover);
}

/* ── Status badges ── */
.status {
    padding: 0.25rem 0.625rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.status.active {
    background: var(--color-active-bg);
    color: var(--color-active-text);
}

.status.maintenance {
    background: var(--color-maintenance-bg);
    color: var(--color-maintenance-text);
}

.status.offline {
    background: var(--color-offline-bg);
    color: var(--color-offline-text);
}

/* ── Buttons ── */
.btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 500;
    font-family: var(--font);
    font-size: 0.9375rem;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.2s;
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
}

.btn-secondary {
    background: var(--color-card);
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-border);
}

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

.btn-danger:hover {
    background: #CC2F26;
}

.btn-sm {
    padding: 0.25rem 0.625rem;
    font-size: 0.8125rem;
}

/* ── Action buttons ── */
.actions {
    display: flex;
    gap: 0.5rem;
}

/* ── Modals ── */
.modal-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--color-overlay);
    z-index: 999;
}

.modal-overlay.active {
    display: block;
}

.modal {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--color-modal-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    z-index: 1000;
    width: 90%;
    max-width: 520px;
    max-height: 90vh;
    overflow-y: auto;
    transition: background-color 0.2s;
}

.modal.active {
    display: block;
}

.modal-header {
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    color: var(--color-text);
    font-weight: 600;
    font-size: 1.0625rem;
}

.btn-close {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--color-text-secondary);
    padding: 0.4rem;
    border-radius: var(--radius-sm);
    transition: all 0.2s;
    font-family: var(--font);
}

.btn-close:hover {
    background: var(--color-card);
    color: var(--color-text);
}

/* ── Forms ── */
form {
    padding: 1.5rem;
}

.form-group {
    margin-bottom: 1rem;
}

label {
    display: block;
    margin-bottom: 0.4rem;
    font-weight: 500;
    font-size: 0.9375rem;
    color: var(--color-text);
}

input, select, textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 0.9375rem;
    font-family: var(--font);
    background: var(--color-input-bg);
    color: var(--color-text);
    transition: border-color 0.2s, background-color 0.2s, color 0.2s;
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.12);
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    margin-top: 1.5rem;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
}

/* ── Loading spinner ── */
.loading-spinner {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--color-surface);
    padding: 2rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    z-index: 1001;
    text-align: center;
}

.loading-spinner.active {
    display: block;
}

.loading-spinner i {
    font-size: 2rem;
    color: var(--color-primary);
    margin-bottom: 1rem;
}

/* ── Responsive ── */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 0.75rem;
    }

    .nav-menu {
        flex-wrap: wrap;
    }

    .section-header {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .data-table {
        overflow-x: auto;
    }

    table {
        min-width: 600px;
    }

    .modal {
        width: 95%;
        margin: 1rem;
    }
}