:root {
    --bg-color: #fffde7; /* Soft yellow */
}

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

body {
    font-family: 'Comic Sans MS', sans-serif;
    background-color: var(--bg-color);
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
    touch-action: none; /* No zooming/scrolling */
}

header {
    display: flex;
    align-items: center;
    padding: 10px 15px;
    background: #fff;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    z-index: 10;
}

.back-btn {
    font-size: 2rem;
    text-decoration: none;
    margin-right: 15px;
}

h1 {
    font-size: 1.5rem;
    color: #ff9800; /* Orange */
    flex-grow: 1;
    text-align: center;
}

#clear-btn {
    background-color: #f44336; /* Red for clear */
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 10px;
    font-size: 1.2rem;
    cursor: pointer;
    font-weight: bold;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

#clear-btn:active {
    transform: scale(0.95);
}

#paint-canvas {
    flex-grow: 1;
    width: 100%;
    cursor: crosshair;
    background-color: var(--bg-color);
}

.fullscreen-btn {
    font-size: 1.5rem;
    background: rgba(255,255,255,0.8);
    border: none;
    border-radius: 50%;
    width: 44px;
    height: 44px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    transition: transform 0.2s;
    flex-shrink: 0;
    text-decoration: none;
    color: inherit;
}
.fullscreen-btn:active {
    transform: scale(0.9);
}