:root {
    --bg-main: #0f172a; /* Slate 900 */
    --bg-card: #1e293b; /* Slate 800 */
    --text-main: #f8fafc; /* Slate 50 */
    --text-muted: #94a3b8; /* Slate 400 */
    --primary: #3b82f6; /* Blue 500 */
    --primary-hover: #2563eb; /* Blue 600 */
    --success: #10b981;
    --danger: #ef4444;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', system-ui, sans-serif; }

body {
    background-color: var(--bg-main);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    min-height: 100vh;
}

/* Memaksa tampilan Mobile (Mobile First View) */
.mobile-app-container {
    width: 100%;
    max-width: 480px;
    background-color: var(--bg-card);
    min-height: 100vh;
    box-shadow: 0 0 20px rgba(0,0,0,0.5);
    position: relative;
    overflow-x: hidden;
}

/* Header & Forms */
.header { padding: 20px; text-align: center; border-bottom: 1px solid #334155; }
.content { padding: 20px; }

.form-group { margin-bottom: 15px; }
.form-group label { display: block; margin-bottom: 5px; color: var(--text-muted); font-size: 0.9em; }
.form-control {
    width: 100%; padding: 12px;
    background: var(--bg-main);
    border: 1px solid #334155;
    color: white; border-radius: 8px;
    outline: none; transition: 0.3s;
}
.form-control:focus { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.3); }

.btn {
    width: 100%; padding: 12px;
    border: none; border-radius: 8px;
    background: var(--primary); color: white;
    font-weight: bold; cursor: pointer; transition: 0.3s;
}
.btn:hover { background: var(--primary-hover); }

.alert { padding: 12px; border-radius: 8px; margin-bottom: 15px; font-size: 0.9em; }
.alert-error { background: rgba(239, 68, 68, 0.2); color: var(--danger); border: 1px solid var(--danger); }
.alert-success { background: rgba(16, 185, 129, 0.2); color: var(--success); border: 1px solid var(--success); }

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }