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

:root {
    --bg: #f0eef5;
    --card-bg: #ffffff;
    --text: #1a1a2e;
    --text-muted: #8888a0;
    --accent: #7b5ea7;
    --accent-light: #c9b8e8;
    --accent-gradient: linear-gradient(135deg, #7b5ea7, #9b7fd4, #b8a0e8);
    --border: #e0dce8;
    --radius: 16px;
    --tab-height: 64px;
    --header-height: 56px;
    --safe-bottom: env(safe-area-inset-bottom, 0px);
    --safe-top: env(safe-area-inset-top, 0px);
}

html, body {
    height: 100%;
    overflow: hidden;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    -webkit-text-size-adjust: 100%;
    -webkit-tap-highlight-color: transparent;
}

/* Header */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: calc(var(--header-height) + var(--safe-top));
    padding-top: var(--safe-top);
    background: var(--text);
    background: linear-gradient(135deg, #1a1a2e 0%, #2d2b55 100%);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
}

header h1 {
    font-size: 18px;
    font-weight: 700;
    letter-spacing: 1.5px;
    text-transform: uppercase;
}

/* Upload screen */
.upload-screen {
    position: fixed;
    top: calc(var(--header-height) + var(--safe-top));
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    padding: 28px 20px;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    background: linear-gradient(180deg, var(--bg) 0%, #e8e4f0 100%);
}

.upload-card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 32px 24px;
    width: 100%;
    max-width: 400px;
    box-shadow: 0 4px 20px rgba(123, 94, 167, 0.08), 0 1px 3px rgba(0,0,0,0.04);
    text-align: center;
}

.upload-card h2 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
}

#collage-preview {
    margin-top: 16px;
}

#collage-preview canvas {
    width: 100%;
    border-radius: 12px;
    border: 2px solid var(--border);
    cursor: grab;
}

#collage-preview canvas:active {
    cursor: grabbing;
}

#collage-preview .btn {
    margin: 4px;
}

.layer-panel {
    display: flex;
    flex-direction: row;
    gap: 8px;
    overflow-x: auto;
    padding: 8px 4px;
    margin-top: 8px;
    -webkit-overflow-scrolling: touch;
}

.layer-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    flex-shrink: 0;
    cursor: pointer;
    padding: 6px;
    border-radius: 10px;
    border: 2px solid var(--border);
    background: var(--card-bg);
    transition: border-color 0.15s;
}

.layer-item.layer-active {
    border-color: var(--accent);
    background: #f3eeff;
}

.layer-item canvas {
    width: 44px;
    height: 44px;
    border-radius: 6px;
    border: none;
    display: block;
}

.layer-btns {
    display: flex;
    gap: 4px;
}

.layer-btn {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
    width: 24px;
    height: 24px;
    font-size: 10px;
    cursor: pointer;
    color: var(--text);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.layer-btn:active {
    background: var(--accent-light);
}

/* Main content */
main {
    position: fixed;
    top: calc(var(--header-height) + var(--safe-top));
    bottom: calc(var(--tab-height) + var(--safe-bottom));
    left: 0;
    right: 0;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    background: linear-gradient(180deg, var(--bg) 0%, #e8e4f0 100%);
}

.tab-content {
    display: none;
    padding: 16px;
    padding-bottom: 24px;
}

.tab-content.active {
    display: block;
}

/* Cards */
.section-card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 20px;
    margin-bottom: 16px;
    box-shadow: 0 4px 20px rgba(123, 94, 167, 0.06), 0 1px 3px rgba(0,0,0,0.03);
}

.section-card h2 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
    letter-spacing: 0.3px;
}

.hint {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 8px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 22px;
    background: var(--text);
    color: #fff;
    border: none;
    border-radius: 50px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    -webkit-appearance: none;
    touch-action: manipulation;
    min-height: 44px;
    letter-spacing: 0.3px;
    transition: transform 0.15s, box-shadow 0.15s;
}

.btn:active {
    transform: scale(0.96);
    box-shadow: 0 2px 8px rgba(123, 94, 167, 0.3);
}

.btn-small {
    padding: 8px 16px;
    font-size: 13px;
    min-height: 36px;
}

/* Reference toolbar */
.ref-toolbar {
    display: flex;
    gap: 8px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}

.ref-toolbar .btn-small {
    background: var(--bg);
    color: var(--text);
    border: 1.5px solid var(--border);
}

.ref-toolbar .btn-small:active {
    background: var(--accent-light);
}

.ref-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
    margin-bottom: 8px;
}

.ref-canvas-wrap {
    position: relative;
    margin: 12px 0;
}

.extract-controls {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 8px;
}

/* Upload zone */
.upload-zone {
    border: 2px dashed var(--accent-light);
    border-radius: var(--radius);
    padding: 40px 16px;
    text-align: center;
    cursor: pointer;
    touch-action: manipulation;
    transition: border-color 0.2s, background 0.2s;
    background: rgba(123, 94, 167, 0.03);
}

.upload-zone:active {
    border-color: var(--accent);
    background: rgba(123, 94, 167, 0.08);
}

.upload-zone p {
    color: var(--text-muted);
    font-size: 16px;
}

/* Palette rows */
.palette-row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 12px 0;
}

.swatch {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    border: 2px solid var(--border);
    cursor: pointer;
    position: relative;
    touch-action: manipulation;
    transition: transform 0.15s, box-shadow 0.15s;
}

.swatch:active {
    transform: scale(0.92);
}

.swatch.in-active {
    border-color: var(--accent);
    box-shadow: 0 0 0 2px var(--accent), 0 2px 8px rgba(123, 94, 167, 0.3);
}

.swatch .swatch-label {
    position: absolute;
    bottom: -18px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 10px;
    color: var(--text-muted);
    white-space: nowrap;
}

.active-palette .swatch {
    width: 56px;
    height: 56px;
}

.active-palette .swatch .remove-btn {
    position: absolute;
    top: -6px;
    right: -6px;
    width: 20px;
    height: 20px;
    background: var(--text);
    color: #fff;
    border-radius: 50%;
    font-size: 12px;
    line-height: 20px;
    text-align: center;
    display: none;
    cursor: pointer;
}

.active-palette .swatch:hover .remove-btn,
.active-palette .swatch:active .remove-btn {
    display: block;
}

/* Range inputs */
input[type="range"] {
    -webkit-appearance: none;
    width: 120px;
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    margin: 0 8px;
    vertical-align: middle;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 24px;
    height: 24px;
    background: var(--accent);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 6px rgba(123, 94, 167, 0.3);
}

input[type="color"] {
    -webkit-appearance: none;
    width: 44px;
    height: 44px;
    border: 2px solid var(--border);
    border-radius: 12px;
    padding: 2px;
    cursor: pointer;
    background: none;
}

input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 0;
}

input[type="color"]::-webkit-color-swatch {
    border: none;
    border-radius: 9px;
}

label {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    color: var(--text-muted);
}

/* Canvas */
canvas {
    width: 100%;
    border-radius: 12px;
    touch-action: none;
}

/* Grid number labels */
.grid-number {
    position: absolute;
    font-size: 11px;
    color: rgba(255,255,255,0.8);
    text-shadow: 0 1px 2px rgba(0,0,0,0.5);
    pointer-events: none;
}

/* Paint tab */
.suggestion-card {
    background: var(--bg);
    border-radius: 12px;
    padding: 14px;
    margin-bottom: 10px;
}

.suggestion-card .match-label {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.suggestion-card .mix-row {
    display: flex;
    align-items: center;
    gap: 8px;
}

.suggestion-card .mini-swatch {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    border: 1px solid var(--border);
    flex-shrink: 0;
}

.suggestion-card .pigment-name {
    font-size: 14px;
    font-weight: 600;
}

.suggestion-card .pigment-code {
    font-size: 12px;
    color: var(--text-muted);
}

.temp-indicator {
    font-size: 13px;
    font-weight: 500;
    min-width: 50px;
}

.temp-indicator.warm {
    color: #b05ce6;
}

.temp-indicator.cool {
    color: #5e8fd4;
}

.temp-indicator.neutral {
    color: var(--text-muted);
}

/* Color map legend */
.colormap-legend {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 10px;
    margin: 16px 0 8px;
}

.legend-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.legend-swatch {
    width: 52px;
    height: 52px;
    border-radius: 12px;
    border: 2px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
}

.legend-num {
    font-size: 20px;
    font-weight: 700;
    text-shadow: 0 1px 2px rgba(0,0,0,0.2);
}

.legend-label {
    font-size: 11px;
    color: var(--text-muted);
    font-family: monospace;
}

/* Pigment grid */
.pigment-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 8px;
}

.pigment-card {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px;
    background: var(--bg);
    border-radius: 12px;
    font-size: 12px;
    cursor: pointer;
    touch-action: manipulation;
    transition: transform 0.15s;
}

.pigment-card:active {
    transform: scale(0.97);
}

.pigment-card .pig-swatch {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    border: 1px solid var(--border);
    flex-shrink: 0;
}

.pigment-card .pig-name {
    font-weight: 600;
    line-height: 1.2;
}

.pigment-card .pig-code {
    color: var(--text-muted);
    font-size: 11px;
}

.pigment-card .pig-temp {
    font-size: 11px;
    margin-left: auto;
}

/* Tab bar */
.tab-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: calc(var(--tab-height) + var(--safe-bottom));
    padding-bottom: var(--safe-bottom);
    background: var(--card-bg);
    border-top: 1px solid var(--border);
    display: flex;
    z-index: 100;
    box-shadow: 0 -2px 12px rgba(0,0,0,0.04);
}

.tab-btn {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 3px;
    border: none;
    background: none;
    color: var(--text-muted);
    font-size: 10px;
    font-weight: 500;
    cursor: pointer;
    touch-action: manipulation;
    -webkit-appearance: none;
    padding: 0;
    transition: color 0.2s;
}

.tab-btn.active {
    color: var(--accent);
}

.tab-btn svg {
    width: 22px;
    height: 22px;
}

/* Utilities */
.hidden {
    display: none !important;
}

.mix-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
}

/* Toast notification */
.toast {
    position: fixed;
    bottom: calc(var(--tab-height) + var(--safe-bottom) + 16px);
    left: 50%;
    transform: translateX(-50%);
    background: var(--text);
    color: #fff;
    padding: 10px 20px;
    border-radius: 50px;
    font-size: 13px;
    font-weight: 500;
    z-index: 200;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
    box-shadow: 0 4px 12px rgba(26, 26, 46, 0.2);
}

.toast.show {
    opacity: 1;
}

/* Responsive - iPad+ */
@media (min-width: 768px) {
    main {
        max-width: 600px;
        margin: 0 auto;
        left: 50%;
        transform: translateX(-50%);
    }

    .upload-card {
        max-width: 440px;
    }

    .palette-row {
        gap: 10px;
    }

    .swatch {
        width: 56px;
        height: 56px;
    }

    .pigment-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}