/* ============================================
   Background Remover - Apple-like Design
   ============================================ */

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

:root {
    /* Colors */
    --color-primary: #007AFF;
    --color-primary-hover: #0066D6;
    --color-secondary: #5856D6;
    --color-success: #34C759;
    --color-background: #F5F5F7;
    --color-surface: #FFFFFF;
    --color-text: #1D1D1F;
    --color-text-secondary: #86868B;
    --color-border: #D2D2D7;
    --color-border-light: #E8E8ED;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);

    /* Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

body {
    font-family: var(--font-family);
    background-color: var(--color-background);
    color: var(--color-text);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   App Container
   ============================================ */

.app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ============================================
   Header
   ============================================ */

.header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border-light);
    padding: 16px 24px;
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 18px;
    font-weight: 600;
    color: var(--color-text);
}

.header-info {
    display: flex;
    gap: 8px;
}

.badge {
    padding: 6px 12px;
    background: rgba(52, 199, 89, 0.1);
    color: var(--color-success);
    font-size: 12px;
    font-weight: 600;
    border-radius: 20px;
}

/* ============================================
   Main Content
   ============================================ */

.main {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
}

/* ============================================
   Upload Zone
   ============================================ */

.upload-zone {
    background: var(--color-surface);
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-xl);
    padding: 80px 60px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-normal);
    max-width: 600px;
    width: 100%;
}

.upload-zone:hover,
.upload-zone.drag-over {
    border-color: var(--color-primary);
    background: rgba(0, 122, 255, 0.02);
}

.upload-zone.drag-over {
    transform: scale(1.02);
}

.upload-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.upload-icon {
    margin-bottom: 8px;
    opacity: 0.8;
}

.upload-zone h2 {
    font-size: 24px;
    font-weight: 600;
    color: var(--color-text);
}

.upload-zone p {
    color: var(--color-text-secondary);
    font-size: 15px;
}

.first-load-note {
    font-size: 13px !important;
    color: var(--color-text-secondary) !important;
    margin-top: 16px;
}

/* ============================================
   Loading State
   ============================================ */

.loading-state {
    text-align: center;
    max-width: 400px;
    width: 100%;
}

.loading-content {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: 60px 40px;
    box-shadow: var(--shadow-md);
}

.spinner {
    width: 60px;
    height: 60px;
    border: 4px solid var(--color-border-light);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 24px;
}

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

.loading-state h2 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
}

.loading-state p {
    color: var(--color-text-secondary);
    font-size: 14px;
    margin-bottom: 24px;
}

.progress-bar {
    height: 6px;
    background: var(--color-border-light);
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
    width: 0%;
    transition: width 0.3s ease;
    animation: progress-pulse 2s ease-in-out infinite;
}

@keyframes progress-pulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.7;
    }
}

/* ============================================
   Buttons
   ============================================ */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    font-size: 15px;
    font-weight: 500;
    font-family: inherit;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.btn-primary:hover {
    background: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

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

/* ============================================
   Editor Layout
   ============================================ */

.editor {
    display: flex;
    gap: 24px;
    width: 100%;
    max-width: 1400px;
    height: calc(100vh - 120px);
}

.canvas-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 16px;
    min-width: 0;
}

.canvas-container {
    flex: 1;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;

    /* Checkerboard pattern for transparency */
    background-image:
        linear-gradient(45deg, #e0e0e0 25%, transparent 25%),
        linear-gradient(-45deg, #e0e0e0 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #e0e0e0 75%),
        linear-gradient(-45deg, transparent 75%, #e0e0e0 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    background-color: #f0f0f0;
}

.canvas-container canvas {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

/* ============================================
   Controls Panel
   ============================================ */

.controls-panel {
    width: 320px;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    overflow-y: auto;
}

.panel-section {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.panel-section h3 {
    font-size: 13px;
    font-weight: 600;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Sliders */
.slider-row {
    display: flex;
    align-items: center;
    gap: 12px;
}

.slider-row label {
    font-size: 14px;
    color: var(--color-text-secondary);
    min-width: 60px;
}

.slider {
    flex: 1;
    -webkit-appearance: none;
    appearance: none;
    height: 6px;
    background: var(--color-border-light);
    border-radius: 3px;
    outline: none;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--color-primary);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 6px rgba(0, 122, 255, 0.3);
    transition: all var(--transition-fast);
}

.slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--color-primary);
    border-radius: 50%;
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 6px rgba(0, 122, 255, 0.3);
}

.slider-value {
    min-width: 40px;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-text);
    text-align: right;
}

.hint {
    font-size: 12px;
    color: var(--color-text-secondary);
    line-height: 1.4;
}

/* Brush Modes */
.brush-modes {
    display: flex;
    gap: 8px;
}

.brush-mode {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 12px;
    font-size: 13px;
    font-weight: 500;
    font-family: inherit;
    background: var(--color-background);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-sm);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.brush-mode:hover {
    border-color: var(--color-border);
}

.brush-mode.active {
    background: rgba(0, 122, 255, 0.1);
    border-color: var(--color-primary);
    color: var(--color-primary);
}

/* Undo/Redo Row */
.undo-redo-row {
    display: flex;
    gap: 8px;
    margin-top: 8px;
}

.btn-icon {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 8px 12px;
    font-size: 12px;
    font-weight: 500;
    font-family: inherit;
    background: var(--color-surface);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-sm);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-icon:hover:not(:disabled) {
    background: var(--color-background);
    border-color: var(--color-border);
    color: var(--color-text);
}

.btn-icon:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Actions */
.panel-section.actions {
    margin-top: auto;
    padding-top: 24px;
    border-top: 1px solid var(--color-border-light);
    gap: 8px;
}

.panel-section.actions .btn {
    width: 100%;
}

/* ============================================
   Cursor Styles
   ============================================ */

.canvas-container.brushing {
    cursor: none;
}

/* Brush Cursor */
.brush-cursor {
    position: fixed;
    pointer-events: none;
    border: 2px solid var(--color-primary);
    border-radius: 50%;
    z-index: 1000;
    display: none;
}

.brush-cursor.active {
    display: block;
}

.brush-cursor.erase {
    border-color: #FF3B30;
}

.brush-cursor.restore {
    border-color: #34C759;
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 900px) {
    .editor {
        flex-direction: column;
        height: auto;
    }

    .canvas-area {
        min-height: 400px;
    }

    .controls-panel {
        width: 100%;
    }

    .header-info {
        display: none;
    }
}

@media (max-width: 600px) {
    .upload-zone {
        padding: 40px 24px;
    }

    .upload-zone h2 {
        font-size: 20px;
    }

    .main {
        padding: 16px;
    }

    .controls-panel {
        padding: 16px;
    }
}