:root {
    /* Light Theme Variables */
    --bg-color: #f0f2f5;
    --canvas-bg: #ffffff;
    --text-color: #333333;
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(255, 255, 255, 0.4);
    --accent: #4a90e2;
    --hover-bg: rgba(0, 0, 0, 0.05);
}

body.dark-theme {
    /* Dark Theme Variables */
    --bg-color: #1a1a1a;
    --canvas-bg: #222222;
    --text-color: #eeeeee;
    --glass-bg: rgba(40, 40, 40, 0.85);
    --glass-border: rgba(255, 255, 255, 0.1);
    --accent: #64b5f6;
    --hover-bg: rgba(255, 255, 255, 0.1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    user-select: none;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    overflow: hidden; /* Canvas handles zoom/pan, no body scroll */
    transition: background-color 0.3s ease, color 0.3s ease;
}

.hidden {
    display: none !important;
}

/* UI Elements */
.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.1);
}

/* Join Overlay */
.overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.overlay-card {
    padding: 2.5rem;
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    text-align: center;
    width: 90%;
    max-width: 400px;
}

.overlay-card input {
    padding: 0.8rem;
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    background: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
    outline: none;
}
.overlay-card input:focus { border-color: var(--accent); }

.overlay-card button {
    padding: 0.8rem;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    transition: transform 0.1s, filter 0.2s;
}
.overlay-card button:hover { filter: brightness(1.1); }
.overlay-card button:active { transform: scale(0.98); }

/* App Layout */
#app {
    display: flex;
    height: 100vh;
    width: 100vw;
}

/* Sidebar */
.sidebar {
    width: 250px;
    height: 100%;
    position: absolute;
    left: 0;
    top: 0;
    z-index: 10;
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--glass-border);
    transition: transform 0.3s ease;
}

@media (max-width: 768px) {
    /* Hide sidebar on small screens or make it a drawer */
    .sidebar { transform: translateX(-100%); }
    .toolbar { width: 90%; flex-wrap: wrap; justify-content: center; bottom: 10px; gap: 0.5rem; }
    .tool-group { padding-right: 0.5rem; gap: 0.2rem; }
    .tool-btn { font-size: 1rem; }
}

.sidebar-header {
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--glass-border);
}

.status {
    width: 12px; height: 12px;
    border-radius: 50%;
    box-shadow: 0 0 5px currentColor;
}
.status.connected { background-color: #4CAF50; color: #4CAF50; }
.status.disconnected { background-color: #F44336; color: #F44336; }

#user-list {
    list-style: none;
    overflow-y: auto;
    flex: 1;
}

.user-item {
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 1px solid var(--glass-border);
    font-weight: 500;
}
.user-color {
    width: 16px; height: 16px;
    border-radius: 50%;
    border: 1px solid rgba(0,0,0,0.1);
}

/* Toolbar */
.toolbar {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 10;
    padding: 0.5rem 1rem;
    border-radius: 12px;
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.tool-group {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.tool-group:not(:last-child) {
    border-right: 1px solid var(--glass-border);
    padding-right: 1.5rem;
}

.tool-btn {
    background: transparent;
    border: none;
    font-size: 1.25rem;
    padding: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    color: var(--text-color);
    transition: background 0.2s, transform 0.1s;
}

.tool-btn:hover { background: var(--hover-bg); }
.tool-btn:active { transform: scale(0.95); }
.tool-btn.active { background: var(--accent); color: white; }

input[type="color"] {
    -webkit-appearance: none;
    border: none;
    width: 32px;
    height: 32px;
    border-radius: 6px;
    cursor: pointer;
    background: transparent;
}
input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
input[type="color"]::-webkit-color-swatch { border: none; border-radius: 6px; box-shadow: 0 0 2px rgba(0,0,0,0.3); }

input[type="range"] {
    accent-color: var(--accent);
}

/* Canvas Container */
.canvas-container {
    position: relative;
    width: 100vw;
    height: 100vh;
    background-color: var(--canvas-bg);
    overflow: hidden;
}

/* Important: touch-action none allows us to capture all touch gestures natively 
   without the browser interfering with pull-to-refresh or native zoom */
canvas {
    position: absolute;
    top: 0; left: 0;
    touch-action: none;
}

/* Dynamic canvas should be on top */
#dynamic-canvas {
    z-index: 2;
    pointer-events: all; 
}
#static-canvas {
    z-index: 1;
    pointer-events: none; /* Let dynamic canvas handle all events */
}