:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #eff6ff;
    --success: #10b981;
    --danger: #ef4444;
    --bg-dark: #0f172a;
    --card-bg: #1e293b;
    --border-color: #334155;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --radius: 12px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.installer-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    width: 100%;
    max-width: 680px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    overflow: hidden;
}

.installer-header {
    padding: 30px;
    background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
    border-bottom: 1px solid var(--border-color);
    text-align: center;
}

.brand-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 1.75rem;
    font-weight: 800;
    color: #38bdf8;
    letter-spacing: -0.5px;
    margin-bottom: 8px;
}

.brand-badge {
    background: #0284c7;
    color: #fff;
    font-size: 0.75rem;
    padding: 3px 8px;
    border-radius: 6px;
    font-weight: 700;
    text-transform: uppercase;
}

.installer-subtitle {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.stepper-container {
    display: flex;
    justify-content: space-between;
    padding: 20px 30px;
    background: #172033;
    border-bottom: 1px solid var(--border-color);
}

.step-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
}

.step-circle {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: #334155;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    font-weight: 700;
}

.step-item.active {
    color: #38bdf8;
}

.step-item.active .step-circle {
    background: #0284c7;
    box-shadow: 0 0 12px rgba(2, 132, 199, 0.5);
}

.step-item.completed {
    color: var(--success);
}

.step-item.completed .step-circle {
    background: var(--success);
}

.installer-body {
    padding: 30px;
}

.step-panel {
    display: none;
}

.step-panel.active {
    display: block;
    animation: fadeIn 0.3s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
}

.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: #e2e8f0;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    background: #0f172a;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: #fff;
    font-size: 0.95rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: #38bdf8;
    box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.2);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
}

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

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

.btn-secondary {
    background: #334155;
    color: #e2e8f0;
}

.btn-secondary:hover {
    background: #475569;
}

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

.btn-success:hover {
    background: #059669;
}

.btn-w100 {
    width: 100%;
}

.alert-box {
    padding: 14px 18px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-size: 0.9rem;
    display: none;
}

.alert-danger {
    background: rgba(239, 68, 68, 0.15);
    border: 1px solid var(--danger);
    color: #fca5a5;
}

.alert-success {
    background: rgba(16, 185, 129, 0.15);
    border: 1px solid var(--success);
    color: #6ee7b7;
}

.req-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 24px;
}

.req-table th, .req-table td {
    padding: 10px 14px;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.9rem;
    text-align: left;
}

.req-table th {
    color: var(--text-muted);
    font-weight: 600;
    background: #172033;
}

.status-badge {
    padding: 3px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
}

.status-badge.pass {
    background: rgba(16, 185, 129, 0.2);
    color: #34d399;
}

.status-badge.fail {
    background: rgba(239, 68, 68, 0.2);
    color: #f87171;
}

.footer-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 24px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.loading-spinner {
    display: inline-block;
    width: 18px;
    height: 18px;
    border: 2px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}