:root {
    --bg-color: #f0f2f5;
    --text-color: #1a1a1a;
    --card-bg: #ffffff;
    --card-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
    --primary-color: #4CAF50;
    --primary-hover: #45a049;
    --accent-color: #2196F3;
    --surface-color: #ffffff;
    --border-color: #e0e0e0;
    --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    
    /* Transitions */
    --theme-transition: background-color 0.3s ease, color 0.3s ease, box-shadow 0.3s ease;
}

body.dark-theme {
    --bg-color: #0f172a;
    --text-color: #f1f5f9;
    --card-bg: #1e293b;
    --card-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
    --surface-color: #334155;
    --border-color: #475569;
}

body {
    font-family: var(--font-main);
    margin: 0;
    padding: 2rem;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    transition: var(--theme-transition);
}

h1 {
    margin-bottom: 2rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    text-align: center;
}

/* Theme Toggle Container */
.controls {
    position: fixed;
    top: 1rem;
    right: 1rem;
    z-index: 100;
}