:root {
    color-scheme: light dark;
    --bg-page: #F9FAFB;
    --bg-card: #FFFFFF;
    --text-primary: #111827;
    --text-secondary: #4B5563;
    --text-tertiary: #9CA3AF;
    --accent-color: #2563EB;
    --accent-hover: #1D4ED8;
    --border-color: #E5E7EB;
    --success-bg: #ECFDF5;
    --success-text: #047857;
    --success-border: #A7F3D0;
    --error-bg: #FEF2F2;
    --error-text: #DC2626;
    --error-border: #FCA5A5;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);

    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-mono: 'Fira Code', ui-monospace, SFMono-Regular, monospace;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-page: #111827;
        --bg-card: #1F2937;
        --text-primary: #F9FAFB;
        --text-secondary: #D1D5DB;
        --text-tertiary: #9CA3AF;
        --accent-color: #3B82F6;
        --accent-hover: #60A5FA;
        --border-color: #374151;
        --success-bg: rgba(4, 120, 87, 0.14);
        --success-text: #6EE7B7;
        --success-border: rgba(110, 231, 183, 0.24);
        --error-bg: rgba(220, 38, 38, 0.1);
        --error-text: #FCA5A5;
        --error-border: rgba(220, 38, 38, 0.2);
    }
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-page);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}
.hidden { display: none !important; }

.app-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.app-header {
    padding: 3rem 0;
    text-align: center;
}
.app-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}
.app-subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
    padding-bottom: 4rem;
}

.upload-section {
    max-width: 600px;
    width: 100%;
    margin: 0 auto;
}

.upload-card {
    background-color: var(--bg-card);
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    padding: 3rem 2rem;
    text-align: center;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
    cursor: pointer;
}
.upload-card:hover, .upload-card.dragover {
    border-color: var(--accent-color);
    background-color: var(--bg-page);
}
.upload-card:focus-within {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.15);
}

.upload-icon-wrapper {
    width: 48px;
    height: 48px;
    margin: 0 auto 1.5rem;
    color: var(--text-secondary);
}
.upload-icon {
    width: 100%;
    height: 100%;
}
.upload-card:hover .upload-icon-wrapper, .upload-card.dragover .upload-icon-wrapper {
    color: var(--accent-color);
}

.upload-heading {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}
.upload-text {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.btn-primary {
    display: inline-block;
    background-color: var(--accent-color);
    color: #ffffff;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    font-weight: 500;
    font-size: 0.95rem;
    border: none;
    cursor: pointer;
    transition: background-color 0.2s ease;
}
.btn-secondary {
    display: inline-block;
    background-color: var(--bg-card);
    color: var(--text-primary);
    padding: 0.75rem 1rem;
    border-radius: 6px;
    font-weight: 500;
    font-size: 0.95rem;
    border: 1px solid var(--border-color);
    cursor: pointer;
    transition: border-color 0.2s ease, color 0.2s ease, background-color 0.2s ease;
}
.btn-primary:hover:not(:disabled) {
    background-color: var(--accent-hover);
}
.btn-secondary:hover:not(:disabled) {
    border-color: var(--accent-color);
    color: var(--accent-color);
}
.btn-primary:focus-visible,
.btn-secondary:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.35);
    outline-offset: 2px;
}
.btn-primary:disabled,
.btn-secondary:disabled {
    cursor: not-allowed;
    opacity: 0.65;
}

.file-limits {
    margin-top: 1.5rem;
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

.preview-container {
    width: 100%;
}

.preview-card {
    background-color: var(--bg-card);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}
#imagePreview {
    width: 100%;
    max-height: 320px;
    object-fit: contain;
    border-radius: 6px;
    background-color: var(--bg-page);
}
.selected-file {
    display: grid;
    gap: 0.5rem;
    margin-top: 1rem;
    padding: 1rem;
    background-color: var(--bg-page);
    border: 1px solid var(--border-color);
    border-radius: 6px;
}
.summary-item {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}
.summary-item strong {
    color: var(--text-primary);
    font-weight: 600;
}
.summary-item span:last-child {
    text-align: right;
    overflow-wrap: anywhere;
}
.preview-actions {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 0.75rem;
    margin-top: 1rem;
}

.loading-state {
    text-align: center;
    padding: 3rem 0;
}
.spinner-ring {
    width: 32px;
    height: 32px;
    margin: 0 auto 1rem;
    border: 3px solid var(--border-color);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spinner 0.8s linear infinite;
}
.loading-state p {
    color: var(--text-secondary);
    font-weight: 500;
}

.error-banner {
    background-color: var(--error-bg);
    color: var(--error-text);
    border: 1px solid var(--error-border);
    padding: 1rem 1.5rem;
    border-radius: 8px;
    margin-top: 1.5rem;
    font-weight: 500;
    text-align: center;
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    gap: 1rem;
    margin-bottom: 2rem;
}
.result-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}
.result-header p {
    color: var(--text-secondary);
    overflow-wrap: anywhere;
}
.result-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 0.75rem;
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.data-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    min-width: 0;
}

.card-wide {
    grid-column: 1 / -1;
}

.card-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
    color: var(--text-primary);
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.metadata-content {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.metadata-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.metadata-key {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

.metadata-value {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    color: var(--text-primary);
    background-color: var(--bg-page);
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    word-break: normal;
    overflow-wrap: break-word;
}
.metadata-value.is-long {
    word-break: break-all;
    overflow-wrap: anywhere;
}

.no-data {
    color: var(--text-tertiary);
    font-style: italic;
    font-size: 0.9rem;
}
.category-description {
    display: none;
}

.app-footer {
    padding: 2rem 0;
    color: var(--text-tertiary);
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}
.footer-link {
    color: var(--text-tertiary);
    width: 2rem;
    height: 2rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    border: 1px solid transparent;
    transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}
.footer-link:hover {
    color: var(--text-primary);
    border-color: var(--border-color);
    background-color: var(--bg-card);
}
.footer-link:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.35);
    outline-offset: 2px;
}
.footer-icon {
    width: 1.15rem;
    height: 1.15rem;
    background-color: currentColor;
    display: block;
    -webkit-mask: url("../img/github.svg") center / contain no-repeat;
    mask: url("../img/github.svg") center / contain no-repeat;
}

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

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}

@media (min-width: 768px) {
    .metadata-item {
        flex-direction: row;
        align-items: baseline;
        justify-content: space-between;
        gap: 1rem;
    }
    .metadata-key {
        flex-shrink: 0;
    }
    .metadata-value {
        text-align: right;
    }
}

@media (max-width: 480px) {
    .app-container {
        padding: 0 1rem;
    }
    .app-header {
        padding: 2rem 0;
    }
    .upload-card {
        padding: 2rem 1rem;
    }
    #imagePreview {
        max-height: 240px;
    }
    .preview-actions,
    .result-header {
        grid-template-columns: 1fr;
    }
    .preview-actions {
        display: grid;
    }
    .result-header {
        display: grid;
        align-items: start;
    }
    .result-actions {
        justify-content: stretch;
    }
    .result-actions .btn-secondary {
        flex: 1 1 100%;
    }
    .summary-item {
        flex-direction: column;
        gap: 0.1rem;
    }
    .summary-item span:last-child {
        text-align: left;
    }
    .cards-grid {
        grid-template-columns: 1fr;
    }
}