:root {
    --bg-color: #f4f4f4;
    --text-color: #111;
    --highlight-bg: #ffcc00;
}

body.dark {
    --bg-color: #111;
    --text-color: #f4f4f4;
    --highlight-bg: #00bcd4;
}

body {
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: Arial, sans-serif;
    transition: background-color 0.4s ease, color 0.4s ease;
}

.container {
    text-align: center;
}

h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
}

.highlight {
    background-color: var(--highlight-bg);
    padding: 10px 20px;
    border-radius: 12px;
    transition: background-color 0.4s ease;
}

.toggle-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    padding: 10px 16px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
}

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 1.2s ease forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}