/* Diff Checker: page-local editor and result styling. */
.diff-checker-tool {
    --diff-border: var(--border-color);
    --diff-gutter: var(--bs-secondary-bg);
    --diff-removed-row: rgba(var(--bs-danger-rgb), 0.08);
    --diff-removed-inline: rgba(var(--bs-danger-rgb), 0.28);
    --diff-added-row: rgba(var(--bs-success-rgb), 0.09);
    --diff-added-inline: rgba(var(--bs-success-rgb), 0.3);
}

.diff-editor-panel {
    min-width: 0;
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-areas:
        "heading file"
        "editor editor"
        "meta meta";
}

.diff-editor-heading {
    grid-area: heading;
    min-width: 0;
    align-self: start;
}

.diff-file-action {
    grid-area: file;
    min-width: 0;
    align-self: start;
    margin-bottom: 0.5rem;
}

.diff-drop-zone {
    grid-area: editor;
}

.diff-editor-meta {
    grid-area: meta;
}

/* Keep keyboard focus visible across every Diff Checker control, including
 * the native file-picker buttons. */
.diff-checker-tool :is(button, textarea, input[type="checkbox"]):focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 3px;
    box-shadow: 0 0 0 0.2rem rgba(var(--bs-primary-rgb), 0.2);
}

.diff-drop-zone {
    position: relative;
    border: 1px solid var(--diff-border);
    border-radius: var(--radius-sm);
    background: var(--card-bg);
    transition: border-color var(--transition-speed) ease, box-shadow var(--transition-speed) ease, background-color var(--transition-speed) ease;
}

.diff-drop-zone.is-dragging {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(var(--bs-primary-rgb), 0.12);
    background-color: var(--bs-primary-bg-subtle);
}

.diff-input {
    display: block;
    min-height: 300px;
    border: 0;
    border-radius: inherit;
    background: transparent;
    color: var(--text-color);
    font-family: var(--bs-font-monospace);
    font-size: 0.86rem;
    line-height: 1.55;
    resize: vertical;
    box-shadow: none !important;
}

.diff-input:focus {
    background: transparent;
}

.diff-drop-hint {
    position: absolute;
    right: 0.75rem;
    bottom: 0.65rem;
    padding: 0.2rem 0.45rem;
    border-radius: 0.25rem;
    background: var(--bs-secondary-bg);
    color: var(--text-muted);
    font-size: 0.72rem;
    pointer-events: none;
    opacity: 0.85;
}

.diff-options {
    border-color: var(--diff-border) !important;
    background: var(--bs-tertiary-bg);
}

.diff-compare-status {
    display: flex;
    align-items: flex-start;
    gap: 0.65rem;
    padding: 0.75rem 0.9rem;
    border: 1px solid var(--diff-border);
    border-left-width: 0.25rem;
    border-radius: var(--radius-sm);
    background: var(--bs-tertiary-bg);
    color: var(--text-color);
}

.diff-compare-status-icon {
    flex: 0 0 auto;
    margin-top: 0.1rem;
    font-size: 1.05rem;
}

.diff-compare-status.is-identical {
    border-color: rgba(var(--bs-success-rgb), 0.35);
    border-left-color: var(--bs-success);
    background: var(--bs-success-bg-subtle);
}

.diff-compare-status.is-identical .diff-compare-status-icon {
    color: var(--bs-success-text-emphasis);
}

.diff-compare-status.is-different {
    border-color: rgba(var(--bs-primary-rgb), 0.3);
    border-left-color: var(--primary-color);
    background: var(--bs-primary-bg-subtle);
}

.diff-compare-status.is-different .diff-compare-status-icon {
    color: var(--primary-color);
}

.diff-compare-status.is-empty .diff-compare-status-icon,
.diff-compare-status.is-neutral .diff-compare-status-icon {
    color: var(--text-muted);
}

.diff-stat {
    padding: 0.45rem 0.65rem;
    font-weight: 600;
    border: 1px solid transparent;
}

.diff-stat-added {
    color: var(--bs-success-text-emphasis);
    background: var(--bs-success-bg-subtle);
    border-color: rgba(var(--bs-success-rgb), 0.2);
}

.diff-stat-removed {
    color: var(--bs-danger-text-emphasis);
    background: var(--bs-danger-bg-subtle);
    border-color: rgba(var(--bs-danger-rgb), 0.2);
}

.diff-stat-changed {
    color: var(--bs-warning-text-emphasis);
    background: var(--bs-warning-bg-subtle);
    border-color: rgba(var(--bs-warning-rgb), 0.2);
}

.diff-stat-unchanged {
    color: var(--bs-secondary-color);
    background: var(--bs-secondary-bg);
    border-color: var(--diff-border);
}

.diff-legend-swatch {
    display: inline-block;
    width: 0.75rem;
    height: 0.75rem;
    margin-right: 0.25rem;
    vertical-align: -0.08rem;
    border: 1px solid var(--diff-border);
    border-radius: 0.15rem;
}

.diff-removed-swatch { background: var(--diff-removed-inline); }
.diff-added-swatch { background: var(--diff-added-inline); }
.diff-modified-swatch { background: var(--bs-warning-bg-subtle); }
.diff-unchanged-swatch { background: var(--card-bg); }

.diff-result-view {
    overflow: hidden;
    border: 1px solid var(--diff-border);
    border-radius: var(--radius-sm);
    background: var(--card-bg);
}

#diff-result {
    scroll-margin-top: 1rem;
}

.diff-split-head,
.diff-unified-head {
    display: grid;
    grid-template-columns: 1fr 1fr;
    padding: 0.65rem 0.75rem;
    border-bottom: 1px solid var(--diff-border);
    background: var(--bs-secondary-bg);
    color: var(--text-muted);
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.diff-unified-head {
    display: block;
}

.diff-split-head span + span {
    padding-left: 0.75rem;
    border-left: 1px solid var(--diff-border);
}

.diff-split-body,
.diff-unified-body {
    max-height: 620px;
    overflow: auto;
    font-family: var(--bs-font-monospace);
    font-size: 0.82rem;
    line-height: 1.55;
}

.diff-split-row {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    min-width: 0;
}

.diff-side-line,
.diff-unified-line {
    display: flex;
    min-width: 0;
    min-height: 1.55em;
    border-bottom: 1px solid rgba(var(--bs-secondary-rgb), 0.08);
}

.diff-side-line + .diff-side-line {
    border-left: 1px solid var(--diff-border);
}

.diff-line-number {
    flex: 0 0 3.25rem;
    padding: 0.18rem 0.55rem;
    background: var(--diff-gutter);
    color: var(--text-muted);
    text-align: right;
    user-select: none;
}

.diff-line-content {
    min-width: 0;
    flex: 1 1 auto;
    padding: 0.18rem 0.7rem;
    white-space: pre-wrap;
    overflow-wrap: anywhere;
    color: var(--text-color);
}

.diff-side-line.is-added,
.diff-unified-line.is-added {
    background: var(--diff-added-row);
}

.diff-side-line.is-removed,
.diff-unified-line.is-removed {
    background: var(--diff-removed-row);
}

.diff-side-line.is-changed,
.diff-unified-line.is-changed {
    background: var(--bs-warning-bg-subtle);
}

.diff-inline-added,
.diff-inline-removed {
    display: inline;
    border-radius: 0.18rem;
    font-weight: 700;
}

.diff-inline-added {
    background: var(--diff-added-inline);
    color: var(--bs-success-text-emphasis);
}

.diff-inline-removed {
    background: var(--diff-removed-inline);
    color: var(--bs-danger-text-emphasis);
    text-decoration: line-through;
    text-decoration-thickness: 1px;
}

.diff-unified-line {
    display: flex;
}

.diff-unified-prefix {
    flex: 0 0 2rem;
    padding: 0.18rem 0.45rem;
    color: var(--text-muted);
    text-align: center;
    user-select: none;
}

.diff-unified-line.is-added .diff-unified-prefix { color: var(--bs-success-text-emphasis); }
.diff-unified-line.is-removed .diff-unified-prefix { color: var(--bs-danger-text-emphasis); }

.diff-empty-state {
    padding: 2rem 1rem;
    color: var(--text-muted);
    text-align: center;
}

@media (max-width: 767.98px) {
    .diff-split-head {
        display: none;
    }

    .diff-split-row {
        display: block;
    }

    .diff-side-line {
        border-left: 0 !important;
    }

    .diff-side-line + .diff-side-line {
        border-top: 1px dashed var(--diff-border);
    }

    .diff-side-line::before {
        display: block;
        flex: 0 0 4.8rem;
        padding: 0.18rem 0.45rem;
        color: var(--text-muted);
        font-family: var(--bs-body-font-family);
        font-size: 0.7rem;
        font-weight: 600;
        text-align: right;
        text-transform: uppercase;
        content: attr(data-side-label);
    }

    .diff-line-number {
        display: none;
    }

    .diff-line-content {
        padding-left: 0.45rem;
    }
}

@media (max-width: 575.98px) {
    .diff-input {
        min-height: 240px;
    }

    .diff-drop-hint {
        display: none;
    }

    .diff-result-view {
        margin-right: -0.1rem;
        margin-left: -0.1rem;
    }
}