:root {
    --bg-color: #0d1117;
    --panel-bg: rgba(22, 27, 34, 0.65);
    --panel-border: rgba(255, 255, 255, 0.1);
    --text-main: #f0f6fc;
    --text-muted: #8b949e;
    --accent-color: #58a6ff;
    --accent-hover: #3182ce;
    --input-bg: rgba(13, 17, 23, 0.8);
    --input-border: rgba(255, 255, 255, 0.15);
    --input-focus: #58a6ff;
    --danger: #f85149;
    --success: #2ea043;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    position: relative;
    padding: 2rem;
}

/* Background Animated Blobs */
.blob-bg {
    position: absolute;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(88, 166, 255, 0.15) 0%, rgba(0, 0, 0, 0) 70%);
    border-radius: 50%;
    top: -100px;
    left: -100px;
    z-index: -1;
    filter: blur(60px);
    animation: drift 20s infinite alternate ease-in-out;
}

.blob-bg.blob-2 {
    background: radial-gradient(circle, rgba(163, 113, 247, 0.15) 0%, rgba(0, 0, 0, 0) 70%);
    top: auto;
    bottom: -150px;
    left: auto;
    right: -100px;
    animation: drift-reverse 25s infinite alternate ease-in-out;
}

@keyframes drift {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(100px, 100px) scale(1.1); }
}

@keyframes drift-reverse {
    0% { transform: translate(0, 0) scale(1.1); }
    100% { transform: translate(-150px, -50px) scale(1); }
}

/* Glassmorphism Panel */
.glass-panel {
    background: var(--panel-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--panel-border);
    border-radius: 24px;
    padding: 3rem;
    width: 100%;
    max-width: 1200px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    z-index: 10;
}

/* 2-Column Layout */
.main-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
    align-items: start;
}

.preview-column {
    display: flex;
    flex-direction: column;
    min-height: 500px;
    height: 720px;
    position: sticky;
    top: 2rem;
}

#3d-preview-container {
    flex-grow: 1;
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--panel-border);
    border-radius: 16px;
    position: relative;
    overflow: hidden;
}

#preview-loading {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 1.1rem;
    position: absolute;
    z-index: 5;
}

#3d-preview-container canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    cursor: grab;
    z-index: 10;
}

#3d-preview-container canvas:active {
    cursor: grabbing;
}

header {
    text-align: center;
    margin-bottom: 2.5rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #58a6ff, #a371f7);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* Location Hint */
.location-hint {
    background: rgba(88, 166, 255, 0.1);
    border: 1px solid rgba(88, 166, 255, 0.2);
    border-radius: 12px;
    padding: 1rem 1.25rem;
    margin-bottom: 2rem;
    display: flex;
    gap: 1rem;
    align-items: flex-start;
    font-size: 0.9rem;
    color: var(--text-main);
    line-height: 1.5;
}

.location-hint svg {
    color: var(--accent-color);
    flex-shrink: 0;
    margin-top: 2px;
}

.location-hint code {
    background: rgba(0, 0, 0, 0.3);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: monospace;
    color: #a371f7;
    word-break: break-all;
    font-size: 0.85rem;
}

/* Tooltip Warning Icon */
.tooltip-icon {
    position: relative;
    display: inline-flex;
    align-items: center;
    vertical-align: middle;
    margin-left: 4px;
    color: #f59e0b;
    cursor: help;
    outline: none;
}

.tooltip-icon svg {
    color: #f59e0b;
    flex-shrink: 0;
    transition: color 0.2s ease;
}

.tooltip-icon:hover svg,
.tooltip-icon:focus svg {
    color: #fbbf24;
}

.tooltip-text {
    visibility: hidden;
    opacity: 0;
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%);
    background: rgba(13, 17, 23, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(245, 158, 11, 0.3);
    color: #fde68a;
    padding: 0.6rem 0.8rem;
    border-radius: 8px;
    font-size: 0.78rem;
    line-height: 1.45;
    width: 260px;
    text-align: left;
    font-weight: 400;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    transition: opacity 0.2s ease, visibility 0.2s ease;
    z-index: 100;
    pointer-events: none;
}

.tooltip-text::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 6px solid transparent;
    border-top-color: rgba(245, 158, 11, 0.3);
}

.tooltip-icon:hover .tooltip-text,
.tooltip-icon:focus .tooltip-text {
    visibility: visible;
    opacity: 1;
}

/* File Drop Zone */
.file-drop-area {
    border: 2px dashed var(--input-border);
    border-radius: 12px;
    padding: 1.5rem 1.5rem;
    text-align: center;
    transition: all 0.3s ease;
    background: rgba(0, 0, 0, 0.2);
    margin-bottom: 1.25rem;
    position: relative;
}

.file-drop-area.dragover {
    border-color: var(--accent-color);
    background: rgba(88, 166, 255, 0.05);
}

.file-drop-area.has-file {
    border-style: solid;
    border-color: var(--success);
    background: rgba(46, 160, 67, 0.05);
}

.upload-icon {
    color: var(--text-muted);
    margin-bottom: 1rem;
    transition: color 0.3s ease;
}

.file-drop-area.dragover .upload-icon, .file-drop-area.has-file .upload-icon {
    color: var(--accent-color);
}

.file-drop-area.has-file .upload-icon {
    color: var(--success);
}

.drop-text {
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.or-text {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.file-name-display {
    margin-top: 1rem;
    font-weight: 600;
    color: var(--success);
    word-break: break-all;
}

/* Buttons */
.btn-primary, .btn-accent {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    font-family: inherit;
}

.btn-primary {
    background-color: var(--input-bg);
    color: var(--text-main);
    border: 1px solid var(--panel-border);
}

.btn-primary:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
}

.btn-accent {
    width: 100%;
    background: linear-gradient(135deg, #58a6ff, #3182ce);
    color: white;
    padding: 1rem;
    font-size: 1.1rem;
    margin-top: 1rem;
    box-shadow: 0 4px 14px 0 rgba(88, 166, 255, 0.39);
}

.btn-accent:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(88, 166, 255, 0.23);
    background: linear-gradient(135deg, #69b4ff, #4293df);
}

.btn-accent:disabled {
    background: #30363d;
    color: var(--text-muted);
    cursor: not-allowed;
    box-shadow: none;
}

/* Configuration Grid */
.config-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 0.3rem;
}

input[type="number"], select {
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    color: var(--text-main);
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    font-size: 0.9rem;
    font-family: inherit;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input[type="number"]:focus, select:focus {
    outline: none;
    border-color: var(--input-focus);
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.3);
}

/* Custom Checkbox */
.checkbox-group {
    margin-bottom: 1rem;
}

.custom-checkbox {
    display: flex;
    align-items: center;
    cursor: pointer;
    font-weight: 500;
    user-select: none;
}

.custom-checkbox input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}

.checkmark {
    height: 24px;
    width: 24px;
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 6px;
    margin-right: 12px;
    position: relative;
    transition: all 0.2s ease;
}

.custom-checkbox:hover input ~ .checkmark {
    border-color: var(--accent-color);
}

.custom-checkbox input:checked ~ .checkmark {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

.checkmark:after {
    content: "";
    position: absolute;
    display: none;
    left: 8px;
    top: 4px;
    width: 6px;
    height: 12px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.custom-checkbox input:checked ~ .checkmark:after {
    display: block;
}

/* Status Message */
.status-message {
    margin-top: 1.5rem;
    padding: 1rem;
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
    animation: fadeIn 0.3s ease;
}

.status-message.hidden {
    display: none;
}

.status-message.error {
    background: rgba(248, 81, 73, 0.1);
    color: var(--danger);
    border: 1px solid rgba(248, 81, 73, 0.3);
}

.status-message.success {
    background: rgba(46, 160, 67, 0.1);
    color: var(--success);
    border: 1px solid rgba(46, 160, 67, 0.3);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 900px) {
    .main-layout {
        grid-template-columns: 1fr;
    }
    .preview-column {
        height: 400px;
        min-height: 400px;
    }
}

@media (max-width: 600px) {
    .config-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .glass-panel {
        padding: 2rem 1.5rem;
    }
}

/* Bone Tree View */
.bone-tree-container {
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 8px;
    max-height: 180px;
    overflow-y: scroll;
    padding: 0.5rem;
    margin-bottom: 1rem;
}

/* Custom Scrollbar for Bone Tree */
.bone-tree-container::-webkit-scrollbar {
    width: 6px;
}
.bone-tree-container::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 4px;
}
.bone-tree-container::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.15);
    border-radius: 4px;
}
.bone-tree-container::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.3);
}

.bone-tree-empty {
    padding: 1rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    font-style: italic;
}

.bone-group details summary {
    cursor: pointer;
    font-weight: 500;
    color: var(--text-main);
    list-style: none; 
    display: flex;
    align-items: center;
    padding: 0.4rem 0.5rem;
    border-radius: 4px;
    transition: background 0.2s;
}

.bone-group details summary:hover {
    background: rgba(255, 255, 255, 0.05);
}

.bone-group details summary::-webkit-details-marker {
    display: none;
}

.bone-group details summary::before {
    content: '▶';
    font-size: 0.7em;
    color: var(--accent-color);
    margin-right: 8px;
    transition: transform 0.2s;
}

.bone-group details[open] summary::before {
    transform: rotate(90deg);
}

.tree-cb {
    margin-right: 8px;
    accent-color: var(--accent-color);
    cursor: pointer;
    width: 16px;
    height: 16px;
    vertical-align: middle;
}

.cb-label {
    cursor: pointer;
    user-select: none;
    vertical-align: middle;
}

.tree-children {
    padding-left: 2rem;
    padding-bottom: 0.5rem;
    display: grid;
    grid-template-columns: 1fr 1fr; 
    gap: 4px;
}

.bone-item {
    font-size: 0.85rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    padding: 2px 0;
}

.bone-item:hover {
    color: var(--text-main);
}