:root {
    --primary-color: #2c3e50; /* Abu-abu tua elegan */
    --accent-color: #3498db; /* Biru cerah */
    --background-color: #ecf0f1; /* Abu-abu muda */
    --text-color: #34495e;
    --card-bg: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
    position: relative;
    transition: background-color 0.5s ease;
}

/* Animasi latar belakang */
body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--primary-color) 100%);
    opacity: 0.1;
    z-index: -1;
    animation: background-pulse 15s infinite alternate ease-in-out;
}

@keyframes background-pulse {
    from { transform: scale(1); }
    to { transform: scale(1.1); }
}

/* Containers */
.container {
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease, visibility 0.6s;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 90%;
    max-width: 600px;
}

.container.active {
    opacity: 1;
    visibility: visible;
    transform: translate(-50%, -50%);
}

.card {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 10px 30px var(--shadow-color);
    text-align: center;
    transition: transform 0.3s ease-in-out;
}

.card:hover {
    transform: translateY(-5px);
}

/* Login section */
.input-group {
    margin: 20px 0;
}
input {
    width: 100%;
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 16px;
    box-sizing: border-box;
    transition: border-color 0.3s;
}
input:focus {
    outline: none;
    border-color: var(--accent-color);
}
button {
    background-color: var(--primary-color);
    color: white;
    padding: 14px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
}
button:hover {
    background-color: var(--accent-color);
    transform: scale(1.05);
}

/* Quiz section */
.quiz-card h2 {
    font-weight: 600;
    margin-bottom: 30px;
    color: var(--primary-color);
    font-size: 1.5rem;
}

.answers-grid {
    display: grid;
    gap: 15px;
    grid-template-columns: 1fr;
    margin-bottom: 20px;
}
.answer-btn {
    background-color: var(--background-color);
    color: var(--text-color);
    padding: 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s, border-color 0.3s, transform 0.2s;
    text-align: left;
    font-size: 16px;
}
.answer-btn:hover {
    background-color: #e9ecef;
    border-color: var(--accent-color);
}
.answer-btn.correct {
    background-color: #2ecc71; /* Hijau */
    color: white;
    border-color: #2ecc71;
}
.answer-btn.incorrect {
    background-color: #e74c3c; /* Merah */
    color: white;
    border-color: #e74c3c;
}
.answer-btn.correct, .answer-btn.incorrect {
    pointer-events: none; /* Nonaktifkan klik setelah memilih */
    animation: pulse-border 1s forwards;
}

@keyframes pulse-border {
    0% { box-shadow: 0 0 0 0 rgba(46, 204, 113, 0.7); }
    100% { box-shadow: 0 0 0 10px rgba(46, 204, 113, 0); }
}

/* Progress Bar */
.progress-bar-container {
    height: 8px;
    background-color: #ddd;
    border-radius: 4px;
    margin-top: 10px;
    overflow: hidden;
}
.progress-bar {
    height: 100%;
    width: 0%;
    background-color: var(--accent-color);
    transition: width 0.5s ease-in-out;
}