:root {
    --bg-color: #f8fafc;
    --panel-bg: rgba(255, 255, 255, 0.85);
    --text-color: #1e293b;
    --text-muted: #64748b;
    --accent-color: #6366f1;
    --accent-hover: #4f46e5;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

.dark {
    --bg-color: #0f172a;
    --panel-bg: rgba(15, 23, 42, 0.85);
    --text-color: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: #1e293b;
    --accent-color: #818cf8;
    --accent-hover: #a5b4fc;
}

body {
    margin: 0;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.title {
    font-size: 1.5rem;
    font-weight: 800;
    margin: 0;
    background: linear-gradient(135deg, #6366f1, #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Cursor Preview */
#brushCursor {
    position: fixed;
    pointer-events: none;
    z-index: 9999;
    display: none;
    transition: transform 0.05s ease-out;
    transform: translate(-2px, -22px); /* Align pencil tip to mouse */
}

#brushCursor i {
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.2));
}

.dark #brushCursor i {
    filter: drop-shadow(0 2px 4px rgba(255,255,255,0.1));
}

/* Tool Styling */
.tool-group {
    display: flex;
    align-items: center;
    gap: 12px;
    padding-right: 24px;
    border-right: 1px solid var(--border-color);
}

.tool {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-muted);
}

input[type="number"],
select,
input[type="text"] {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-color);
    font-size: 0.875rem;
    color: var(--text-color);
    outline: none;
    transition: all 0.2s ease;
}

input:focus, select:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

/* Buttons */
button {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
}

.primary-btn { background: var(--accent-color); color: white; }
.primary-btn:hover { background: var(--accent-hover); transform: translateY(-1px); }

.eraser-btn { background: #fee2e2; color: #ef4444; }
.eraser-btn:hover { background: #fecaca; }
.eraser-btn.active { background: #ef4444; color: white; }

/* Collapsible Sidebar (Left) */
.sidebar-left {
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    width: 320px;
    background: var(--panel-bg);
    backdrop-filter: blur(25px);
    border-right: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 500;
    overflow: visible;
}

.sidebar-scroll-area {
    height: 100%;
    width: 85%;
    display: flex;
    flex-direction: column;
    padding: 40px 24px;
    gap: 40px;
    overflow-y: auto;
    overflow-x: hidden;
    scrollbar-width: thin;
    scrollbar-color: var(--accent-color) transparent;
}

.sidebar-left.collapsed {
    transform: translateX(-100%);
}

/* Toggle Button */
.sidebar-toggle-container {
    position: fixed;
    top: 50px;
    left: 320px;
    z-index: 999;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: none;
}

.sidebar-toggle-container.collapsed {
    transform: translateX(-320px);
}

.sidebar-toggle {
    width: 60px;
    height: 80px;
    background-color: #4f46e5;
    color: #ffffff;
    border: 2px solid #ffffff;
    border-left: none;
    border-radius: 0 16px 16px 0;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 10px 5px 25px rgba(0, 0, 0, 0.2);
    pointer-events: auto;
    transition: all 0.2s ease;
}

.sidebar-toggle::after {
    content: "MENU";
    font-size: 10px;
    font-weight: 900;
    letter-spacing: 1px;
    writing-mode: vertical-rl;
    text-orientation: mixed;
}

.sidebar-section {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 32px;
}

.sidebar-title {
    font-size: 0.75rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    user-select: none;
}

.sidebar-title::after {
    content: "+";
    font-size: 1rem;
    transition: transform 0.3s ease;
}

details[open] .sidebar-title::after {
    transform: rotate(45deg);
}

.floating-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 12px;
}

/* Canvas Area */
.canvas-container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
    background-image: 
        radial-gradient(var(--border-color) 1px, transparent 1px),
        radial-gradient(var(--border-color) 1px, transparent 1px);
    background-size: 24px 24px;
    background-position: 0 0, 12px 12px;
}

.canvas-wrapper {
    position: relative;
    max-width: 100%;
    max-height: 100%;
}

canvas {
    background-color: white;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    cursor: none; /* Hidden because of preview cursor */
}

/* Floating Actions */
.canvas-actions {
    position: absolute;
    bottom: calc(100% + 12px);
    right: 0;
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--panel-bg);
    backdrop-filter: blur(20px);
    padding: 6px;
    border-radius: 18px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    z-index: 800;
}

.action-btn {
    width: 56px;
    height: 56px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    border-radius: 14px;
    background: transparent;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.3s ease;
}

.action-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--accent-color);
}

.action-btn i { width: 16px; height: 16px; }

.action-btn span {
    font-size: 0.55rem;
    font-weight: 400;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    opacity: 0.6;
}

.action-divider {
    width: 1px;
    height: 24px;
    background: var(--border-color);
}

/* Modals */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(8px);
    z-index: 1000;
    display: none;
    align-items: center;
    justify-content: center;
}

.modal-backdrop.active { display: flex; }

.modal-content {
    background: var(--bg-color);
    color: var(--text-color);
    width: 90%;
    max-width: 800px;
    border-radius: 32px;
    padding: 48px;
    box-shadow: var(--shadow-lg);
}