:root {
    --bg-color: #f8f9fa;
    --toolbar-bg: rgba(255, 255, 255, 0.9);
    --accent-color: #007bff;
    --text-color: #333;
    --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

body {
    margin: 0;
    padding: 0;
    overflow: hidden;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
}

#canvas {
    display: block;
    cursor: crosshair;
    background-color: white;
    touch-action: none;
}

.toolbar {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--toolbar-bg);
    padding: 10px 20px;
    border-radius: 50px;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 15px;
    backdrop-filter: blur(10px);
    z-index: 100;
    border: 1px solid rgba(0, 0, 0, 0.05);
    max-width: 95vw;
    overflow-x: auto;
    scrollbar-width: none;
}

.toolbar::-webkit-scrollbar {
    display: none;
}

.tool-group {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

.tool-group label {
    display: flex;
    align-items: center;
    gap: 5px;
}

.tool-icon {
    display: none;
    width: 20px;
    height: 20px;
}

label {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-color);
    white-space: nowrap;
}

input[type="color"] {
    border: none;
    width: 30px;
    height: 30px;
    cursor: pointer;
    background: none;
    padding: 0;
    flex-shrink: 0;
}

input[type="range"] {
    width: 100px;
    cursor: pointer;
}

button {
    padding: 8px 16px;
    border: none;
    border-radius: 20px;
    background-color: var(--accent-color);
    color: white;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    white-space: nowrap;
    flex-shrink: 0;
}

button .btn-text {
    display: inline;
}

button .tool-icon {
    display: none;
    width: 20px;
    height: 20px;
}

button:hover {
    background-color: #0056b3;
}

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

button.clear-btn {
    background-color: #dc3545;
}

button.undo-btn {
    background-color: #6c757d;
}

button.undo-btn:hover {
    background-color: #5a6268;
}

button.undo-btn:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

.collab-panel {
    position: fixed;
    top: 85px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--toolbar-bg);
    padding: 10px 20px;
    border-radius: 20px;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 10px;
    z-index: 99;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(0, 0, 0, 0.05);
    font-size: 14px;
}

#peerIdDisplay {
    font-family: monospace;
    background: #eee;
    padding: 2px 6px;
    border-radius: 4px;
    font-weight: bold;
}

#setupMode, #activeMode {
    display: flex;
    align-items: center;
    gap: 10px;
}

@media (max-width: 850px) {
    .toolbar {
        padding: 8px 12px;
        gap: 10px;
    }
    .tool-group label span {
        display: none;
    }
    .tool-icon {
        display: block;
    }
    button .btn-text {
        display: none;
    }
    button .tool-icon {
        display: block;
    }
    button {
        padding: 8px;
        border-radius: 50%;
    }
    input[type="range"] {
        width: 60px;
    }
    .collab-panel {
        top: 75px;
        padding: 8px 12px;
        font-size: 12px;
    }
}

.status {
    position: fixed;
    bottom: 20px;
    right: 20px;
    font-size: 12px;
    color: #888;
    background: rgba(255, 255, 255, 0.7);
    padding: 5px 10px;
    border-radius: 10px;
    pointer-events: none;
}

.hidden-heading {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.hidden { display: none !important; }