:root {
    --color-1: #1A237E;  /* Dark Blue */
    --color-2: #1B5E20;  /* Dark Green */
    --color-3: #B71C1C;  /* Dark Red */
    --color-4: #4A148C;  /* Dark Purple */
    --color-5: #006064;  /* Dark Cyan */
    --color-6: #E65100;  /* Dark Orange */
    --color-7: #3E2723;  /* Dark Brown */
    --color-8: #263238;  /* Dark Blue-Grey */
    --color-9: #880E4F;  /* Dark Pink */
    --color-10: #004D40; /* Dark Teal */
    --color-11: #311B92; /* Dark Indigo */
    --color-12: #BF360C; /* Dark Deep Orange */
    --color-13: #1A237E; /* Another Dark Blue */
    --color-14: #33691E; /* Dark Light Green */
    --color-15: #01579B; /* Dark Light Blue */
    --color-16: #212121; /* Very Dark Grey */
}

body,
html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #f0f0f0;
    font-family: Arial, sans-serif;
}

.grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, 1fr);
    gap: 10px;
    width: 100%;
    height: 100%;
    padding: 10px;
    box-sizing: border-box;
}

.button {
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    color: white;
    border: none;
    cursor: pointer;
    transition: transform 0.1s;
}

.button:hover {
    transform: scale(1.05);
}

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