* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    height: 100vh;
    width: 100vw;
    background-color: #000000;
    font-family: Arial, sans-serif;
    color: white;
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

header {
    position: relative;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 15px 0;
    z-index: 10;
}

header h1 {
    margin: 0;
    font-size: 1.8rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    opacity: 0.5;
}

.home-btn {
    position: absolute;
    left: 20px;
    top: 50%;
    transform: translateY(-50%);
    
    text-decoration: none;
    font-size: 1.5rem;
    padding: 8px 12px;
    background: #333;
    border-radius: 8px;
    transition: 0.2s;
    color: #fff; 
    border: 1px solid #555;
}

.controls {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 30px;
    z-index: 10;
}

button {
    cursor: pointer;
    border: none;
    outline: none;
    box-shadow: 0 4px 10px rgba(0,0,0,0.5);
    transition: transform 0.1s, background-color 0.3s;
    font-weight: bold;
}

button:active {
    transform: scale(0.95);
}

.big-btn {
    padding: 20px 40px;
    font-size: 1.5rem;
    border-radius: 12px;
    background-color: #333;
    color: white;
    border: 2px solid #555;
}

.round-btn {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    font-size: 1.5rem;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #220000;
    border: 2px solid #500;
}

.round-btn.red-active {
    background-color: #ff0000;
    box-shadow: 0 0 15px #ff0000;
    border-color: #ffaaaa;
}

body.light-on {
    background-color: #ffffff;
    color: #333;
}

body.light-on.red-mode {
    background-color: #ff0000;
    color: #000;
}

body.light-on .big-btn {
    background-color: #eee;
    color: #000;
    border-color: #ccc;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

body.light-on.red-mode .big-btn {
    background-color: #300;
    color: #fff;
    border-color: #600;
}