/* ==================== CSS Variables ==================== */
:root {
    /* Colors - Observatory Theme */
    --bg-primary: #fafafa;
    --bg-secondary: #f5f5f5;
    --bg-tertiary: #ffffff;
    
    --accent-primary: #171717;
    --accent-secondary: #2563eb;
    --accent-tertiary: #7c3aed;
    --accent-success: #10b981;
    
    --text-primary: #171717;
    --text-secondary: #525252;
    --text-muted: #a3a3a3;
    
    --border-color: #e5e5e5;
    --border-hover: #d4d4d4;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    
    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;
    --space-2xl: 48px;
    
    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
}

/* ==================== Reset & Base ==================== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

body {
    font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100dvh;
    line-height: 1.6;
}

/* ==================== App Container ==================== */
.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-lg);
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
}

/* ==================== Header ==================== */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: var(--space-lg);
    margin-bottom: var(--space-xl);
}

.header-brand {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.logo {
    width: 48px;
    height: 48px;
    background: var(--accent-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
}

.logo svg {
    width: 26px;
    height: 26px;
    color: white;
}

.brand-text h1 {
    font-size: 1.375rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.brand-text span {
    font-size: 0.8125rem;
    color: var(--text-secondary);
}

.btn-settings {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 0.875rem;
    cursor: pointer;
    transition: var(--transition-fast);
}

.btn-settings svg {
    width: 18px;
    height: 18px;
}

.btn-settings:hover {
    background: var(--bg-secondary);
    border-color: var(--border-hover);
    color: var(--text-primary);
}

/* ==================== Main Content ==================== */
.main-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
    flex: 1;
}

/* ==================== Upload Section ==================== */
.upload-section {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.upload-zone {
    background: var(--bg-tertiary);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-xl);
    min-height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-normal);
    overflow: hidden;
    position: relative;
}

.upload-zone:hover {
    border-color: var(--accent-secondary);
}

.upload-zone.dragover {
    border-color: var(--accent-secondary);
    background: rgba(37, 99, 235, 0.05);
}

.upload-placeholder {
    text-align: center;
    padding: var(--space-xl);
}

.upload-icon {
    width: 80px;
    height: 80px;
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--space-lg);
    transition: var(--transition-fast);
}

.upload-zone:hover .upload-icon {
    background: var(--accent-secondary);
}

.upload-icon svg {
    width: 40px;
    height: 40px;
    color: var(--accent-secondary);
    transition: var(--transition-fast);
}

.upload-zone:hover .upload-icon svg {
    color: white;
}

.upload-placeholder h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.upload-placeholder p {
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
}

.upload-hint {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    font-size: 0.8125rem;
    color: var(--text-muted);
}

.upload-hint .separator {
    color: var(--border-color);
}

/* Image Preview */
.image-preview {
    position: absolute;
    inset: 0;
    display: none;
}

.image-preview.active {
    display: block;
}

.image-preview img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: var(--space-md);
}

.preview-overlay {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition-fast);
}

.image-preview:hover .preview-overlay {
    opacity: 1;
}

.btn-reupload {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    background: white;
    border: none;
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-fast);
}

.btn-reupload svg {
    width: 18px;
    height: 18px;
}

.btn-reupload:hover {
    background: var(--bg-secondary);
}

/* Analysis Options */
.analysis-options {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
}

.analysis-options h4 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
}

.option-item {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    cursor: pointer;
}

.option-item input[type="checkbox"] {
    display: none;
}

.checkmark {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
    flex-shrink: 0;
}

.option-item input:checked + .checkmark {
    background: var(--accent-secondary);
    border-color: var(--accent-secondary);
}

.option-item input:checked + .checkmark::after {
    content: '';
    width: 6px;
    height: 10px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
    margin-bottom: 2px;
}

.option-item span:last-child {
    font-size: 0.9375rem;
    color: var(--text-primary);
}

/* Analyze Button */
.btn-analyze {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    background: var(--accent-primary);
    border: none;
    border-radius: var(--radius-lg);
    color: white;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
    box-shadow: var(--shadow-md);
}

.btn-analyze svg {
    width: 20px;
    height: 20px;
}

.btn-analyze:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

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

.btn-analyze .icon-loading {
    display: none;
    animation: spin 1s linear infinite;
}

.btn-analyze.loading .icon-analyze {
    display: none;
}

.btn-analyze.loading .icon-loading {
    display: block;
}

/* ==================== Results Section ==================== */
.results-section {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-lg);
    overflow-y: auto;
}

.results-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 400px;
    text-align: center;
    color: var(--text-muted);
}

.results-placeholder.hidden {
    display: none;
}

.placeholder-icon {
    width: 80px;
    height: 80px;
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-lg);
}

.placeholder-icon svg {
    width: 40px;
    height: 40px;
}

.results-placeholder h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.results-placeholder p {
    color: var(--text-secondary);
}

.results-content {
    display: none;
    flex-direction: column;
    gap: var(--space-lg);
}

.results-content.active {
    display: flex;
}

/* Result Cards */
.result-card {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.card-header {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.card-icon {
    width: 32px;
    height: 32px;
    background: var(--accent-secondary);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.card-icon svg {
    width: 16px;
    height: 16px;
    color: white;
}

.card-header h4 {
    flex: 1;
    font-size: 0.9375rem;
    font-weight: 600;
}

.btn-copy {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.btn-copy svg {
    width: 16px;
    height: 16px;
}

.btn-copy:hover {
    background: var(--bg-tertiary);
    color: var(--accent-secondary);
}

.card-body {
    padding: var(--space-md);
}

.card-body p {
    font-size: 0.9375rem;
    line-height: 1.7;
    color: var(--text-primary);
}

/* Tags List */
.tags-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.tag {
    padding: var(--space-xs) var(--space-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    font-size: 0.8125rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition-fast);
}

.tag:hover {
    background: var(--accent-secondary);
    border-color: var(--accent-secondary);
    color: white;
}

/* Colors List */
.colors-list {
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.color-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
}

.color-swatch {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.color-hex {
    font-size: 0.75rem;
    font-family: 'SF Mono', monospace;
    color: var(--text-secondary);
}

/* Info Grid */
.info-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
}

.info-item {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.info-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.info-value {
    font-size: 0.9375rem;
    color: var(--text-primary);
    word-break: break-all;
}

/* ==================== Modal ==================== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-normal);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--bg-tertiary);
    border-radius: var(--radius-xl);
    width: 90%;
    max-width: 420px;
    overflow: hidden;
    transform: scale(0.95);
    transition: var(--transition-normal);
}

.modal-overlay.active .modal {
    transform: scale(1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-lg);
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 1.125rem;
    font-weight: 600;
}

.close-btn {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.close-btn svg {
    width: 20px;
    height: 20px;
}

.close-btn:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.modal-body {
    padding: var(--space-lg);
}

.setting-group {
    margin-bottom: var(--space-lg);
}

.setting-group:last-child {
    margin-bottom: 0;
}

.setting-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.setting-group input,
.setting-group select {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 0.9375rem;
    color: var(--text-primary);
    outline: none;
    transition: var(--transition-fast);
}

.setting-group input:focus,
.setting-group select:focus {
    border-color: var(--accent-secondary);
}

.setting-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: var(--space-xs);
}

.modal-footer {
    padding: var(--space-lg);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
}

.btn-primary {
    padding: var(--space-sm) var(--space-xl);
    background: var(--accent-secondary);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    font-family: inherit;
    font-size: 0.9375rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-fast);
}

.btn-primary:hover {
    opacity: 0.9;
}

/* ==================== Footer ==================== */
.footer {
    text-align: center;
    padding: var(--space-xl) 0 var(--space-md);
    color: var(--text-muted);
    font-size: 0.8125rem;
}

/* ==================== Animations ==================== */
@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

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

.result-card {
    animation: fadeIn 0.3s ease;
}

/* ==================== Toast ==================== */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--accent-primary);
    color: white;
    padding: var(--space-sm) var(--space-xl);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    z-index: 1001;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translate(-50%, 20px);
    }
    to {
        opacity: 1;
        transform: translate(-50%, 0);
    }
}

/* ==================== Responsive ==================== */
@media (max-width: 900px) {
    .main-content {
        grid-template-columns: 1fr;
    }
    
    .upload-zone {
        min-height: 300px;
    }
}

@media (max-width: 600px) {
    .app-container {
        padding: var(--space-md);
    }
    
    .header {
        flex-direction: column;
        gap: var(--space-md);
        text-align: center;
    }
    
    .header-brand {
        flex-direction: column;
    }
    
    .options-grid {
        grid-template-columns: 1fr;
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
}

/* ==================== Accessibility ==================== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}

:focus-visible {
    outline: 2px solid var(--accent-secondary);
    outline-offset: 2px;
}