:root {
    --bg-color: #0d1117;
    --panel-bg: rgba(22, 27, 34, 0.75);
    --panel-border: rgba(255, 255, 255, 0.1);
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --accent-color: #4facfe;
    --accent-hover: #00f2fe;
    --accent-glow: rgba(79, 172, 254, 0.4);
    --btn-bg: rgba(255, 255, 255, 0.05);
    --btn-hover: rgba(255, 255, 255, 0.15);
}

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

body {
    background-color: var(--bg-color);
    background-image: radial-gradient(circle at top right, #1a2035, #0d1117 60%);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    overflow: hidden; /* Prevent scrolling body */
    height: 100vh;
    width: 100vw;
}

.app-container {
    display: flex;
    height: 100vh;
    width: 100vw;
}

/* Canvas Area */
.canvas-wrapper {
    flex: 1;
    position: relative;
    overflow: hidden;
    cursor: crosshair;
}

#main-canvas {
    display: block;
    width: 100%;
    height: 100%;
    touch-action: none;
}

#tools-overlay {
    position: absolute;
    top: 20px;
    left: 60px; /* Shift right to avoid overlap with vertical toolbar */
    display: flex;
    gap: 10px;
    z-index: 10;
}

#vertical-toolbar {
    position: absolute;
    top: 20px;
    left: 10px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 10;
    background: var(--panel-bg);
    padding: 10px;
    border-radius: 8px;
    border: 1px solid var(--panel-border);
    backdrop-filter: blur(8px);
}

.tool-btn {
    width: 32px;
    height: 32px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    font-size: 16px;
    background: transparent;
    border: 1px solid transparent;
}

.tool-btn.active {
    background: var(--accent-glow);
    border-color: var(--accent-color);
}

button {
    background: var(--btn-bg);
    border: 1px solid var(--panel-border);
    color: var(--text-primary);
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s ease;
    backdrop-filter: blur(4px);
}

button:hover {
    background: var(--btn-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

button:active {
    transform: translateY(1px);
}

button.primary {
    background: linear-gradient(135deg, var(--accent-color), #00f2fe);
    border: none;
    color: #111;
    font-weight: 600;
}

button.primary:hover {
    box-shadow: 0 0 15px var(--accent-glow);
}

button.secondary {
    background: rgba(40, 50, 70, 0.6);
}

/* Toast Notification */
.toast {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    color: var(--text-primary);
    padding: 10px 20px;
    border-radius: 20px;
    backdrop-filter: blur(10px);
    pointer-events: none;
    transition: opacity 0.3s ease;
    z-index: 50;
}

.toast.hidden { opacity: 0; }
.toast.visible { opacity: 1; }

/* Right Panel */
.panel {
    width: 340px;
    min-width: 340px;
    background: var(--panel-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-left: 1px solid var(--panel-border);
    display: flex;
    flex-direction: column;
    padding: 24px;
    overflow-y: auto;
    box-shadow: -5px 0 25px rgba(0,0,0,0.5);
    z-index: 10;
}

h1 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 24px;
    text-align: center;
    background: linear-gradient(90deg, #e6edf3, #8b949e);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

h2 {
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-secondary);
    margin-bottom: 16px;
    border-bottom: 1px solid var(--panel-border);
    padding-bottom: 8px;
}

.panel-section {
    margin-bottom: 30px;
}

.control-group {
    margin-bottom: 16px;
}

label {
    display: flex;
    justify-content: space-between;
    font-size: 14px;
    margin-bottom: 8px;
    color: var(--text-primary);
}

span[id^="val-"] {
    color: var(--accent-color);
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

/* Custom Range Slider */
input[type=range] {
    -webkit-appearance: none;
    width: 100%;
    background: transparent;
}

input[type=range]:focus {
    outline: none;
}

input[type=range]::-webkit-slider-runnable-track {
    width: 100%;
    height: 6px;
    cursor: pointer;
    background: rgba(255,255,255,0.1);
    border-radius: 3px;
}

input[type=range]::-webkit-slider-thumb {
    height: 16px;
    width: 16px;
    border-radius: 50%;
    background: var(--accent-color);
    cursor: pointer;
    -webkit-appearance: none;
    margin-top: -5px;
    box-shadow: 0 0 10px var(--accent-glow);
    transition: transform 0.1s;
}

input[type=range]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.seed-input-row {
    display: flex;
    gap: 8px;
}

input[type=text] {
    flex: 1;
    background: rgba(0,0,0,0.2);
    border: 1px solid var(--panel-border);
    color: var(--text-primary);
    padding: 8px 12px;
    border-radius: 6px;
    font-family: "Courier New", Courier, monospace;
}

input[type=text]:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px var(--accent-glow);
}

.button-group {
    display: flex;
    gap: 10px;
    margin-bottom: 12px;
}

.button-group button {
    flex: 1;
}

.instructions {
    background: rgba(0,0,0,0.2);
    padding: 16px;
    border-radius: 8px;
    font-size: 13px;
    line-height: 1.5;
    color: var(--text-secondary);
}

.instructions[open] summary {
    margin-bottom: 8px;
    border-bottom: 1px solid var(--panel-border);
    padding-bottom: 8px;
}

.instructions summary {
    cursor: pointer;
    font-size: 14px;
    outline: none;
}
.instructions summary:hover {
    color: var(--accent-hover);
}

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

.instructions ul {
    padding-left: 20px;
    margin-top: 8px;
}

.instructions li {
    margin-bottom: 6px;
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.1);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255,255,255,0.2);
}