:root {
    --bg-color: #1e1e1e;
    --panel-bg: #2d2d2d;
    --text-color: #e0e0e0;
    --accent-color: #007bff;
    --accent-hover: #0056b3;
    --canvas-bg: #888;
    /* Darker background to see the paper */
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    overflow: hidden;
}

#app-container {
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100%;
}

header {
    background-color: var(--panel-bg);
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    z-index: 10;
}

h1 {
    margin: 0;
    font-size: 1.2rem;
    font-weight: 600;
}

.controls {
    display: flex;
    gap: 1rem;
    align-items: center;
}

button,
.upload-btn {
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.2s;
    text-decoration: none;
    display: inline-block;
}

button:hover,
.upload-btn:hover {
    background-color: var(--accent-hover);
}

.control-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
}

.tool-btn {
    background-color: #444;
    padding: 0.3rem 0.6rem;
    font-size: 0.8rem;
    opacity: 0.7;
}

.tool-btn.active {
    background-color: var(--accent-color);
    opacity: 1;
    border: 1px solid white;
}

.status {
    font-size: 0.8rem;
    color: #ffd700;
    /* Gold for status */
    min-width: 150px;
    text-align: right;
    font-weight: 600;
}

select {
    background: #444;
    color: white;
    border: 1px solid #555;
    padding: 0.3rem;
    border-radius: 4px;
    font-family: inherit;
}

main {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #333;
    /* App background */
    overflow: auto;
    position: relative;
    padding: 20px;
}

#canvas-wrapper {
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
    background-color: white;
    /* Paper color */
    touch-action: none;
    /* Critical for Apple Pencil handling */
}

.floating-palette {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--panel-bg);
    padding: 10px 20px;
    border-radius: 30px;
    display: flex;
    gap: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    pointer-events: auto;
    /* Ensure clicks pass */
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
    /* Default hidden/unclickable */
}

.floating-palette.visible {
    opacity: 1;
    pointer-events: auto;
}

.floating-palette button {
    border-radius: 20px;
    font-weight: 600;
    min-width: 80px;
}

#btn-accept {
    background-color: #28a745;
    /* Success Green */
}

#btn-accept:hover {
    background-color: #218838;
}

#btn-clear {
    background-color: #dc3545;
    /* Danger Red */
}

#btn-clear:hover {
    background-color: #c82333;
}

#btn-cycle {
    background-color: var(--accent-color);
}

footer {
    text-align: center;
    padding: 0.5rem;
    font-size: 0.8rem;
    color: #888;
    background-color: var(--panel-bg);
}

/* --- Ghost Options Panel --- */

#ghost-options-wrapper {
    position: absolute;
    bottom: 20px;
    right: 20px;
    z-index: 20;
}

.ghost-toggle-btn {
    background: var(--panel-bg);
    color: var(--text-color);
    border: 1px solid #555;
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: background 0.2s;
}

.ghost-toggle-btn:hover {
    background: #444;
}

.ghost-options {
    background: var(--panel-bg);
    border: 1px solid #444;
    border-radius: 8px;
    padding: 12px 16px;
    margin-top: 8px;
    min-width: 220px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
    transition: max-height 0.3s ease, opacity 0.3s ease, padding 0.3s ease;
    max-height: 400px;
    opacity: 1;
    overflow: hidden;
}

.ghost-options.collapsed {
    max-height: 0;
    opacity: 0;
    padding: 0 16px;
    border: none;
}

.ghost-opt-row {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
    font-size: 0.8rem;
}

.ghost-opt-row label {
    min-width: 70px;
    color: #aaa;
}

.ghost-opt-row input[type="range"] {
    flex: 1;
    accent-color: var(--accent-color);
    height: 4px;
}

.ghost-opt-row span {
    min-width: 35px;
    text-align: right;
    color: #ffd700;
    font-weight: 600;
    font-size: 0.75rem;
}

.checkbox-label {
    cursor: pointer;
    user-select: none;
}

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

/* --- Scene Mode Toggle --- */

.scene-btn {
    background-color: #444;
    padding: 0.3rem 0.6rem;
    font-size: 0.8rem;
    opacity: 0.7;
    border: 1px solid transparent;
    transition: all 0.3s ease;
}

.scene-btn:hover {
    background-color: #555;
    opacity: 0.9;
}

.scene-btn.active {
    background-color: #1a7a3a;
    opacity: 1;
    border: 1px solid #64dc8c;
    box-shadow: 0 0 8px rgba(100, 220, 140, 0.4);
    animation: scene-pulse 2s ease-in-out infinite;
}

@keyframes scene-pulse {

    0%,
    100% {
        box-shadow: 0 0 8px rgba(100, 220, 140, 0.3);
    }

    50% {
        box-shadow: 0 0 16px rgba(100, 220, 140, 0.6);
    }
}