:root {
    --bg-color: #f0f2f5;
    --card-bg: #ffffff;
    --text-color: #333333;
    --number-bg: #f0f0f0;
    --button-bg: #4CAF50;
    --button-hover: #45a049;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

[data-theme='dark'] {
    --bg-color: #1a1a1a;
    --card-bg: #2d2d2d;
    --text-color: #e0e0e0;
    --number-bg: #404040;
    --button-bg: #2e7d32;
    --button-hover: #1b5e20;
    --shadow-color: rgba(0, 0, 0, 0.5);
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: var(--bg-color);
    background-image: url("data:image/svg+xml,%3Csvg width='6' height='6' viewBox='0 0 6 6' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='%239C92AC' fill-opacity='0.1'%3E%3Cpath d='M5 0h1L0 6V5zM6 5v1H5z'/%3E%3C/g%3E%3C/svg%3E%22);
    font-family: sans-serif;
    margin: 0;
    transition: background-color 0.3s ease;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 12px 24px;
    border-radius: 12px;
    border: none;
    background: var(--card-bg);
    color: var(--text-color);
    cursor: pointer;
    font-weight: 600;
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
}

#theme-toggle:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow-color);
}

#theme-toggle:active {
    transform: translateY(0);
}