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

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #212121, #424242);
    color: #fff;
    transition: background 0.5s, color 0.5s;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.canvas {
    text-align: center;
    max-width: 800px;
    padding: 2rem;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    font-weight: 600;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.button-container {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

.button {
    width: 120px;
    height: 120px;
    border: none;
    border-radius: 15px;
    font-size: 1.2rem;
    font-weight: 600;
    color: #333;
    cursor: pointer;
    transition: all 0.3s;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    position: relative;
    overflow: hidden;
}

.button:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

.button:active {
    transform: scale(1.1);
}

.button::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.button:hover::before {
    left: 100%;
}

#grey { background: linear-gradient(135deg, #757575, #9e9e9e); }
#white { background: linear-gradient(135deg, #f5f5f5, #fff); color: #333; }
#blue { background: linear-gradient(135deg, #1976d2, #42a5f5); }
#yellow { background: linear-gradient(135deg, #ffeb3b, #fff176); color: #333; }
.reset { background: linear-gradient(135deg, #f44336, #e57373); color: #fff; }

.h2 {
    font-size: 1.2rem;
    font-weight: 300;
    margin-top: 1rem;
}

.h2 span {
    display: block;
    margin-top: 0.5rem;
}

@media (max-width: 768px) {
    .canvas { padding: 1rem; }
    h1 { font-size: 2rem; }
    .button { width: 100px; height: 100px; font-size: 1rem; }
    .button-container { gap: 0.5rem; }
}