:root {
    --bg-color: #0a0e1a;
    --panel-bg: rgba(20, 27, 45, 0.75);
    --panel-border: rgba(255, 255, 255, 0.08);
    --text-main: #e8ecf4;
    --text-muted: #7a85a0;
    --accent: #06b6d4;
    --accent-hover: #0891b2;
    --accent-glow: rgba(6, 182, 212, 0.35);
    --accent-secondary: #a855f7;
    --input-bg: rgba(10, 14, 26, 0.7);
    --input-border: rgba(122, 133, 160, 0.2);
    --danger: #ef4444;
    --success: #22c55e;
}

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

body {
    font-family: 'Outfit', sans-serif;
    background: var(--bg-color);
    background-image:
        radial-gradient(ellipse at 20% 0%, rgba(6, 182, 212, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 100%, rgba(168, 85, 247, 0.08) 0%, transparent 50%);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 2rem;
}

.app-container {
    max-width: 1300px;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* ── Header ── */
header {
    text-align: center;
    padding: 1rem 0;
}

header h1 {
    font-size: 2.8rem;
    font-weight: 700;
    color: var(--text-main);
    letter-spacing: -0.02em;
}

header h1 .accent {
    background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-muted);
    font-size: 1rem;
    font-weight: 300;
    margin-top: 0.25rem;
    letter-spacing: 0.04em;
}

/* ── Layout ── */
main {
    display: flex;
    gap: 1.5rem;
    align-items: stretch;
}

.controls-section {
    flex: 0 0 380px;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    overflow-y: auto;
    max-height: 80vh;
}

.viewer-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-height: 520px;
}

.glass-panel {
    background: var(--panel-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--panel-border);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 20px 40px -12px rgba(0, 0, 0, 0.6);
}

.section-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--panel-border);
}

/* ── Inputs ── */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.input-group > label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.range-value {
    color: var(--accent);
    font-weight: 700;
    font-size: 0.85rem;
}

input[type="number"] {
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 8px;
    color: var(--text-main);
    padding: 0.7rem 0.9rem;
    font-family: inherit;
    font-size: 0.95rem;
    transition: border-color 0.3s, box-shadow 0.3s;
    width: 100%;
}

input[type="number"]:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

/* ── Range Slider ── */
.range-slider {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--input-border);
    outline: none;
    transition: background 0.2s;
    cursor: pointer;
}

.range-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    box-shadow: 0 0 8px var(--accent-glow);
    transition: transform 0.2s;
}

.range-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.range-slider::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    border: none;
    box-shadow: 0 0 8px var(--accent-glow);
}

/* ── Seed Row ── */
.seed-row {
    display: flex;
    gap: 0.5rem;
}

.seed-row input {
    flex: 1;
}

.icon-btn {
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 8px;
    color: var(--text-main);
    cursor: pointer;
    padding: 0 0.8rem;
    font-size: 1.2rem;
    transition: all 0.2s;
    flex-shrink: 0;
}

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

.toggle-label {
    display: flex !important;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-size: 0.8rem !important;
    color: var(--text-muted) !important;
    text-transform: none !important;
    margin-top: 0.25rem;
}

.toggle-label input[type="checkbox"] {
    accent-color: var(--accent);
    cursor: pointer;
}

/* ── Settings Group ── */
.settings-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--panel-border);
}

/* ── Mode Toggle ── */
.mode-toggle {
    display: flex;
    gap: 0.5rem;
    background: var(--input-bg);
    border-radius: 10px;
    padding: 4px;
    border: 1px solid var(--input-border);
}

.mode-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    background: transparent;
    border: none;
    border-radius: 8px;
    color: var(--text-muted);
    font-family: inherit;
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    transition: all 0.25s ease;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.mode-btn:hover {
    color: var(--text-main);
}

.mode-btn.active {
    background: var(--accent);
    color: white;
    box-shadow: 0 2px 8px var(--accent-glow);
}

/* ── Multi-View Grid ── */
.multiview-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
}

.upload-zone-small {
    height: 150px;
}

.optional-tag {
    font-size: 0.65rem;
    font-weight: 400;
    color: var(--accent);
    text-transform: none;
    letter-spacing: 0;
    opacity: 0.8;
}

/* ── Upload Zone ── */
.upload-zone {
    margin-top: 0.25rem;
    height: 220px;
    border: 2px dashed var(--input-border);
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    background: var(--input-bg);
    cursor: pointer;
    position: relative;
    transition: border-color 0.3s, background 0.3s;
}

.upload-zone:hover {
    border-color: var(--accent);
    background: rgba(6, 182, 212, 0.04);
}

.upload-zone.drag-over {
    border-color: var(--accent);
    background: rgba(6, 182, 212, 0.08);
}

.upload-zone-inner {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-muted);
    text-align: center;
    padding: 1rem;
}

.upload-zone-inner svg {
    opacity: 0.5;
}

.upload-zone-inner span {
    font-size: 0.9rem;
}

.upload-hint {
    font-size: 0.75rem !important;
    opacity: 0.6;
}

.upload-zone img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: none;
}

input[type="file"] {
    display: none;
}

/* ── Primary Button ── */
.primary-btn {
    background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
    color: white;
    border: none;
    border-radius: 10px;
    padding: 0.9rem;
    font-size: 1.05rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-top: auto;
    box-shadow: 0 4px 20px rgba(6, 182, 212, 0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(6, 182, 212, 0.5);
}

.primary-btn:active {
    transform: translateY(0);
}

.primary-btn:disabled {
    background: var(--text-muted);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
    opacity: 0.6;
}

/* ── 3D Viewer ── */
.model-viewer-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: var(--input-bg);
    border-radius: 12px;
    overflow: hidden;
    position: relative;
    border: 1px solid var(--panel-border);
}

.placeholder-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    color: var(--text-muted);
}

.placeholder-icon {
    opacity: 0.3;
}

.status-msg {
    font-size: 1rem;
    font-weight: 400;
}

/* ── Action Buttons ── */
.action-btn {
    position: absolute;
    bottom: 1rem;
    right: 1rem;
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    border-radius: 10px;
    color: var(--text-main);
    cursor: pointer;
    padding: 0.6rem;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
    z-index: 30;
    backdrop-filter: blur(8px);
}

.action-btn:hover {
    background: var(--accent);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px var(--accent-glow);
}

/* ── Progress Bar ── */
.progress-container {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: rgba(255, 255, 255, 0.05);
    z-index: 20;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(to right, var(--accent), var(--accent-secondary));
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 0 3px 3px 0;
}

/* ── History Strip ── */
.history-section {
    padding: 1rem 1.5rem;
}

.history-title {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 0.75rem;
}

.history-strip {
    display: flex;
    gap: 0.75rem;
    overflow-x: auto;
    padding-bottom: 0.5rem;
}

.history-strip::-webkit-scrollbar {
    height: 4px;
}

.history-strip::-webkit-scrollbar-track {
    background: transparent;
}

.history-strip::-webkit-scrollbar-thumb {
    background: var(--input-border);
    border-radius: 2px;
}

.history-item {
    flex-shrink: 0;
    width: 80px;
    height: 80px;
    border-radius: 10px;
    background: var(--input-bg);
    border: 1px solid var(--panel-border);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: all 0.2s ease;
    overflow: hidden;
    position: relative;
}

.history-item:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--accent-glow);
}

.history-item svg {
    opacity: 0.6;
    color: var(--accent);
}

.history-item .history-label {
    font-size: 0.6rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
    text-align: center;
}

/* ── Responsive ── */
@media (max-width: 900px) {
    body {
        padding: 1rem;
    }

    main {
        flex-direction: column;
    }

    .controls-section {
        flex: unset;
        max-height: unset;
    }

    .viewer-section {
        min-height: 400px;
    }

    header h1 {
        font-size: 2rem;
    }
}

/* ── Animations ── */
@keyframes pulse-border {
    0%, 100% { border-color: var(--input-border); }
    50% { border-color: var(--accent); }
}

.generating .model-viewer-container {
    animation: pulse-border 2s ease-in-out infinite;
}