:root {
    --bg-dark: #1e1e1e;
    --bg-panel: #252526;
    --bg-hover: #333333;
    --text-main: #e0e0e0;
    --text-muted: #aaaaaa;
    --accent: #007acc;
    --accent-hover: #0062a3;
    --border: #3e3e42;
    --success: #4caf50;
}

* {
    box-sizing: border-box;
    user-select: none; /* Prevent selection while drawing */
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    height: 100vh;
    display: flex;
    overflow: hidden;
}

/* --- Sidebar --- */
.sidebar {
    width: 310px;
    background-color: var(--bg-panel);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    padding: 20px;
    gap: 20px;
    z-index: 10;
    box-shadow: 2px 0 10px rgba(0,0,0,0.3);
    flex-shrink: 0;
}

.brand {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 10px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border);
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group label {
    font-size: 0.85rem;
    color: var(--text-muted);
    display: flex;
    justify-content: space-between;
}

.value-display {
    color: var(--accent);
    font-weight: 600;
}

/* Inputs */
input[type="range"] {
    -webkit-appearance: none;
    width: 100%;
    height: 6px;
    background: var(--bg-dark);
    border-radius: 3px;
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    transition: background 0.2s;
}

input[type="range"]::-webkit-slider-thumb:hover {
    background: var(--accent-hover);
}

/* Buttons */
.btn {
    background-color: var(--bg-hover);
    color: var(--text-main);
    border: 1px solid var(--border);
    padding: 10px 15px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn:hover {
    background-color: #444;
    border-color: #555;
}

.btn:active {
    transform: translateY(1px);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

.btn-primary {
    background-color: var(--accent);
    border-color: var(--accent);
    color: white;
}

.btn-primary:hover {
    background-color: var(--accent-hover);
}

.btn-secondary {
    background-color: transparent;
}

.btn-secondary:hover {
    background-color: rgba(255,255,255,0.05);
}

.btn-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.zoom-controls {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #1a1a1a;
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 5px;
}

.zoom-btn {
    background: transparent;
    border: none;
    color: var(--text-main);
    padding: 5px 10px;
    cursor: pointer;
    border-radius: 3px;
}

.zoom-btn:hover {
    background: rgba(255,255,255,0.1);
}

.zoom-level {
    font-size: 0.85rem;
    font-family: monospace;
    min-width: 50px;
    text-align: center;
}

/* Instructions Panel */
.instructions {
    margin-top: auto;
    background: rgba(0,0,0,0.2);
    padding: 15px;
    border-radius: 6px;
    font-size: 0.8rem;
    line-height: 1.5;
    color: var(--text-muted);
    border-left: 3px solid var(--accent);
}

.instructions strong {
    color: var(--text-main);
}

.kbd {
    background: #444;
    padding: 2px 6px;
    border-radius: 4px;
    border-bottom: 2px solid #222;
    font-family: monospace;
    color: white;
}

/* --- Workspace --- */
.workspace {
    flex: 1;
    position: relative;
    background-color: #121212;
    /* Checkboard background for transparency */
    background-image: 
        linear-gradient(45deg, #1a1a1a 25%, transparent 25%), 
        linear-gradient(-45deg, #1a1a1a 25%, transparent 25%), 
        linear-gradient(45deg, transparent 75%, #1a1a1a 75%), 
        linear-gradient(-45deg, transparent 75%, #1a1a1a 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    cursor: default;
}

/* Container for canvases */
.canvas-wrapper {
    position: relative;
    box-shadow: 0 0 30px rgba(0,0,0,0.6);
    transform-origin: center center;
    /* Will be transformed by JS */
    transition: transform 0.1s ease-out; 
    cursor: crosshair;
}

.canvas-wrapper.panning {
    cursor: grab;
}

.canvas-wrapper.panning:active {
    cursor: grabbing;
}

canvas {
    display: block;
    touch-action: none; 
}

/* The cursor canvas sits on top */
#cursorCanvas {
    position: absolute;
    top: 0;
    left: 0;
    pointer-events: none; /* Let events pass through to imageCanvas */
    width: 100%;
    height: 100%;
}

/* Hidden file input */
#fileInput {
    display: none;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--bg-panel);
    color: var(--text-main);
    padding: 12px 20px;
    border-radius: 4px;
    border-left: 4px solid var(--success);
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 100;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

/* --- Welcome Message --- */
.welcome-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 5;
    padding: 20px;
}

.welcome-card {
    max-width: 500px;
    background: rgba(37, 37, 38, 0.8);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    padding: 40px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
    animation: fadeIn 0.8s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.welcome-icon {
    color: var(--accent);
    margin-bottom: 20px;
    display: inline-block;
    padding: 20px;
    background: rgba(0, 122, 204, 0.1);
    border-radius: 50%;
}

.welcome-card h1 {
    font-size: 1.8rem;
    margin: 0 0 10px 0;
    color: #fff;
}

.welcome-card p {
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: 30px;
}

.welcome-steps {
    text-align: left;
    margin-bottom: 35px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.step {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--text-main);
    font-size: 0.95rem;
}

.step-num {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background: var(--accent);
    color: #fff;
    border-radius: 50%;
    font-size: 0.8rem;
    font-weight: bold;
    flex-shrink: 0;
}

.btn-large {
    padding: 12px 30px;
    font-size: 1rem;
    font-weight: 600;
    width: 100%;
}

.welcome-footer {
    margin-top: 25px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.welcome-footer a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
}

.welcome-footer a:hover {
    text-decoration: underline;
}

.heart {
    color: #e74c3c;
    font-size: 1rem;
}

.sidebar-footer {
    margin-top: 10px;
    padding-top: 15px;
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
}

.sidebar-footer a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    transition: color 0.2s;
}

.sidebar-footer a:hover {
    color: var(--text-main);
}