:root {
    --bg: #f4f6f9;
    --text: #2c3e50;
    --header: #1f2937;
    --footer: #e5e7eb;
    --button: #2563eb;
    --button-hover: #1d4ed8;
}

body.dark {
    --bg: #111827;
    --text: #f3f4f6;
    --header: #0f172a;
    --footer: #1f2937;
    --button: #3b82f6;
    --button-hover: #2563eb;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    transition: background 0.3s ease, color 0.3s ease;
}

header {
    background: var(--header);
    color: white;
    padding: 20px;
    text-align: center;
}

nav a {
    color: white;
    margin: 0 15px;
    text-decoration: none;
}

nav a:hover {
    text-decoration: underline;
}

.container {
    max-width: 900px;
    margin: 40px auto;
    padding: 20px;
    text-align: center;
    animation: fadeIn 1.2s ease-in-out;
}

button {
    padding: 12px 24px;
    background: var(--button);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: transform 0.2s ease, background 0.3s ease;
}

button:hover {
    background: var(--button-hover);
    transform: scale(1.05);
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    cursor: pointer;
    font-size: 18px;
}
.section {
    margin: 50px 0;
}

.section img {
    width: 100%;
    border-radius: 8px;
    margin-top: 20px;
}

.card {
    background: rgba(255,255,255,0.05);
    padding: 20px;
    border-radius: 8px;
    margin: 20px 0;
}
footer {
    text-align: center;
    padding: 20px;
    background: var(--footer);
    margin-top: 40px;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(15px); }
    to { opacity: 1; transform: translateY(0); }
}