:root {
    --color-background: #f5f7fb;
    --color-surface: #ffffff;
    --color-border: #d8deea;
    --color-text: #1f2933;
    --color-muted: #6b7280;
    --color-success: #16a34a;
    --color-error: #dc2626;
    --color-warning: #d97706;
    --color-pending: #6366f1;
    --shadow: 0 15px 35px rgba(15, 23, 42, 0.08);
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    background: var(--color-background);
    color: var(--color-text);
    display: flex;
    flex-direction: column;
    align-items: center;
}

main {
    width: min(900px, 100%);
    padding: 0 1.5rem 3rem;
}

.app-header {
    width: min(900px, 100%);
    padding: 2.5rem 1.5rem 1rem;
    text-align: center;
}

.app-header h1 {
    margin: 0 0 0.75rem;
    font-size: clamp(1.8rem, 3vw, 2.5rem);
}

.app-header p {
    margin: 0;
    color: var(--color-muted);
    font-size: 1rem;
}

.card {
    background: var(--color-surface);
    border-radius: 24px;
    padding: 2.25rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
    border: 1px solid rgba(148, 163, 184, 0.15);
}

.dropzone {
    border: 2px dashed var(--color-border);
    border-radius: 20px;
    padding: 3rem 2rem;
    text-align: center;
    background: rgba(99, 102, 241, 0.04);
    transition: border-color 0.2s ease, transform 0.2s ease, background 0.2s ease;
    cursor: pointer;
    outline: none;
}

.dropzone:focus-visible {
    border-color: var(--color-pending);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.15);
}

.dropzone.dragover {
    border-color: var(--color-pending);
    background: rgba(99, 102, 241, 0.1);
    transform: translateY(-2px);
}

.dropzone-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.dropzone-title {
    margin: 0 0 0.5rem;
    font-size: 1.25rem;
    font-weight: 600;
}

.dropzone-subtitle {
    margin: 0;
    color: var(--color-muted);
    font-size: 0.95rem;
}

.results-intro {
    margin-top: 0;
    color: var(--color-muted);
}

.metadata {
    background: rgba(148, 163, 184, 0.12);
    border: 1px solid rgba(148, 163, 184, 0.4);
    border-radius: 18px;
    padding: 1.5rem;
    margin-bottom: 1.75rem;
}

.metadata h3 {
    margin: 0 0 1rem;
    font-size: 1.15rem;
}

.metadata-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.metadata-table th {
    text-align: left;
    padding: 0.35rem 0;
    color: var(--color-muted);
    font-weight: 600;
    width: 160px;
}

.metadata-table td {
    padding: 0.35rem 0;
    word-break: break-word;
}

.metadata-more {
    margin-top: 1rem;
}

.metadata-more summary {
    cursor: pointer;
    color: var(--color-pending);
    font-weight: 600;
    outline: none;
}

.metadata-more summary::marker {
    color: var(--color-pending);
}

.metadata-more-content {
    margin-top: 0.75rem;
    display: grid;
    gap: 1rem;
}

@media (min-width: 640px) {
    .metadata-more-content {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

.metadata-more-section h4 {
    margin: 0 0 0.5rem;
    font-size: 0.9rem;
    color: var(--color-muted);
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.metadata-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 0.35rem;
}

.metadata-list li {
    font-size: 0.95rem;
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    gap: 0.35rem;
}

.metadata-list code {
    background: rgba(99, 102, 241, 0.15);
    border-radius: 6px;
    padding: 0.15rem 0.45rem;
    font-size: 0.85rem;
}

.metadata-value {
    color: var(--color-text);
    white-space: pre-wrap;
}

.file-name {
    margin: 0 0 0.5rem;
    font-size: 1.2rem;
    font-weight: 600;
}

.checklist {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 1rem;
}

.check-item {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 1rem;
    align-items: start;
    padding: 1rem 1.25rem;
    border-radius: 16px;
    border: 1px solid transparent;
    background: rgba(148, 163, 184, 0.08);
    transition: background 0.2s ease, border-color 0.2s ease;
}

.check-item .icon {
    font-size: 1.75rem;
    line-height: 1;
    margin-top: 0.2rem;
}

.check-item .label {
    display: block;
    font-weight: 600;
}

.check-item .details {
    margin: 0.35rem 0 0;
    color: var(--color-muted);
    font-size: 0.95rem;
    display: none;
}

.check-item.success {
    border-color: rgba(22, 163, 74, 0.2);
    background: rgba(22, 163, 74, 0.08);
}

.check-item.success .icon {
    color: var(--color-success);
}

.check-item.success .details {
    display: block;
    color: var(--color-success);
}

.check-item.error {
    border-color: rgba(220, 38, 38, 0.2);
    background: rgba(220, 38, 38, 0.08);
}

.check-item.error .icon {
    color: var(--color-error);
}

.check-item.error .details {
    display: block;
    color: var(--color-error);
}

.check-item.warning {
    border-color: rgba(217, 119, 6, 0.2);
    background: rgba(217, 119, 6, 0.08);
}

.check-item.warning .icon {
    color: var(--color-warning);
}

.check-item.warning .details {
    display: block;
    color: var(--color-warning);
}

.check-item.pending .icon {
    color: var(--color-pending);
}

.app-footer {
    width: 100%;
    text-align: center;
    padding: 1.5rem;
    color: var(--color-muted);
    font-size: 0.9rem;
}

.app-footer .small-print {
    margin-top: 0.4rem;
}

.app-footer .credits {
    margin-top: 0.6rem;
    font-weight: 500;
}

.app-footer .credits a {
    color: inherit;
    text-decoration: underline;
    text-decoration-thickness: 0.08em;
}

@media (max-width: 640px) {
    .card {
        padding: 1.75rem;
    }

    .check-item {
        grid-template-columns: 1fr;
    }

    .check-item .icon {
        margin: 0;
    }

    /* Scale GitHub ribbon on mobile */
    .github-ribbon img {
        width: 110px;
        height: auto;
    }
}

/* GitHub ribbon (top-right) */
.github-ribbon {
    position: fixed;
    top: 0;
    right: 0;
    border: 0;
    z-index: 1000;
}

/* Pages list (collapsible under "Checking for pages") */
.pages-collapsible {
    margin-top: 0.5rem;
}
.pages-collapsible summary {
    cursor: pointer;
    color: var(--color-pending);
    font-weight: 600;
}
.pages-list {
    margin: 0.5rem 0 0;
    padding-left: 1.15rem;
}
.pages-list li {
    margin: 0.15rem 0;
}