/* ===== リセット & ベーススタイル ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* カラーパレット */
    --color-bg-primary: hsl(220, 15%, 10%);
    --color-bg-secondary: hsl(220, 15%, 15%);
    --color-bg-tertiary: hsl(220, 15%, 20%);
    --color-text-primary: hsl(220, 15%, 95%);
    --color-text-secondary: hsl(220, 15%, 70%);
    --color-accent: hsl(260, 70%, 60%);
    --color-accent-hover: hsl(260, 70%, 70%);
    --color-success: hsl(150, 60%, 50%);
    --color-border: hsl(220, 15%, 25%);
    
    /* スペーシング */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* 角丸 */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    
    /* シャドウ */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: linear-gradient(135deg, 
        hsl(220, 15%, 8%) 0%, 
        hsl(260, 20%, 12%) 100%);
    color: var(--color-text-primary);
    min-height: 100vh;
    overflow-x: hidden;
}

.container {
    max-width: 1800px;
    margin: 0 auto;
    padding: var(--spacing-lg);
}

/* ===== ヘッダー ===== */
.header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: linear-gradient(135deg, 
        hsla(260, 70%, 60%, 0.1) 0%, 
        hsla(200, 70%, 60%, 0.1) 100%);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--color-border);
}

.title {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, 
        hsl(260, 70%, 70%) 0%, 
        hsl(200, 70%, 70%) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-xs);
}

.subtitle {
    font-size: 1rem;
    color: var(--color-text-secondary);
    font-weight: 500;
}

/* ===== コントロールパネル ===== */
.control-panel {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.control-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.control-label {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.label-text {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-text-secondary);
}

/* ===== ファイル入力 ===== */
.file-input {
    display: none;
}

.drop-zone {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    text-align: center;
    color: var(--color-text-secondary);
    transition: all 0.3s ease;
    cursor: pointer;
    background: var(--color-bg-tertiary);
}

.drop-zone:hover,
.drop-zone.dragover {
    border-color: var(--color-accent);
    background: hsla(260, 70%, 60%, 0.1);
    color: var(--color-text-primary);
}

.drop-zone.ready {
    border-color: var(--color-success);
}

/* ===== スライダー ===== */
.slider {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--color-bg-tertiary);
    outline: none;
    -webkit-appearance: none;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--color-accent);
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.slider::-webkit-slider-thumb:hover {
    background: var(--color-accent-hover);
    transform: scale(1.1);
}

.slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--color-accent);
    cursor: pointer;
    border: none;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.slider::-moz-range-thumb:hover {
    background: var(--color-accent-hover);
    transform: scale(1.1);
}

.slider-value {
    display: inline-block;
    min-width: 3rem;
    padding: 0.25rem 0.75rem;
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-sm);
    text-align: center;
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--color-accent);
}

/* ===== ボタン ===== */
.button-group {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
    box-shadow: var(--shadow-sm);
}

.btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn:active:not(:disabled) {
    transform: translateY(0);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    background: var(--color-accent);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: var(--color-accent-hover);
}

.btn-process {
    background: linear-gradient(135deg, 
        hsl(260, 70%, 60%) 0%, 
        hsl(200, 70%, 60%) 100%);
    color: white;
    flex: 1;
}

.btn-save {
    background: var(--color-success);
    color: white;
}

.btn-secondary {
    background: var(--color-bg-tertiary);
    color: var(--color-text-primary);
    border: 1px solid var(--color-border);
}

/* ===== 画像パネル ===== */
.image-panels {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.panel {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--color-border);
}

.panel-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text-primary);
}

.panel-info {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    font-style: italic;
}

.canvas-wrapper {
    width: 100%;
    height: 500px;
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-md);
    overflow: hidden;
    position: relative;
    cursor: grab;
}

.canvas-wrapper:active {
    cursor: grabbing;
}

.canvas-wrapper canvas {
    display: block;
    max-width: 100%;
    max-height: 100%;
    margin: auto;
}

/* ===== ローディング ===== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(10, 10, 15, 0.9);
    backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: opacity 0.3s ease;
}

.loading-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 4px solid var(--color-bg-tertiary);
    border-top-color: var(--color-accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-text {
    margin-top: var(--spacing-md);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text-primary);
}

/* ===== レスポンシブ ===== */
@media (max-width: 768px) {
    .title {
        font-size: 2rem;
    }
    
    .image-panels {
        grid-template-columns: 1fr;
    }
    
    .control-row {
        grid-template-columns: 1fr;
    }
    
    .canvas-wrapper {
        height: 300px;
    }
}