/*
 * FASS interface foundation
 *
 * This file intentionally exposes opt-in `.ds-*` components. Existing screens
 * can adopt them incrementally without a broad selector changing their layout.
 * Status must always be conveyed by text (or an accessible name), never by
 * colour or animation alone.
 */

:root {
    color-scheme: light;

    /* Typography */
    --ds-font-sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --ds-font-mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
    --ds-text-xs: 0.75rem;
    --ds-text-sm: 0.875rem;
    --ds-text-md: 1rem;
    --ds-text-lg: 1.125rem;
    --ds-text-xl: 1.375rem;
    --ds-leading-tight: 1.25;
    --ds-leading-normal: 1.5;

    /* Spacing and geometry */
    --ds-space-1: 0.25rem;
    --ds-space-2: 0.5rem;
    --ds-space-3: 0.75rem;
    --ds-space-4: 1rem;
    --ds-space-5: 1.25rem;
    --ds-space-6: 1.5rem;
    --ds-space-8: 2rem;
    --ds-radius-sm: 0.5rem;
    --ds-radius-md: 0.75rem;
    --ds-radius-lg: 1rem;
    --ds-touch-target: 2.75rem;

    /* Neutral palette */
    --ds-color-canvas: #f8fafc;
    --ds-color-surface: #ffffff;
    --ds-color-surface-muted: #f1f5f9;
    --ds-color-border: #cbd5e1;
    --ds-color-border-strong: #94a3b8;
    --ds-color-text: #0f172a;
    --ds-color-text-muted: #475569;
    --ds-color-text-subtle: #64748b;
    --ds-color-inverse: #ffffff;

    /* Action and safety semantics */
    --ds-color-action: #1d4ed8;
    --ds-color-action-hover: #1e40af;
    --ds-color-action-soft: #eff6ff;
    --ds-color-info: #1d4ed8;
    --ds-color-info-soft: #eff6ff;
    --ds-color-success: #166534;
    --ds-color-success-soft: #f0fdf4;
    --ds-color-warning: #92400e;
    --ds-color-warning-soft: #fffbeb;
    --ds-color-danger: #b91c1c;
    --ds-color-danger-hover: #991b1b;
    --ds-color-danger-soft: #fef2f2;
    --ds-color-unavailable: #475569;
    --ds-color-unavailable-soft: #f1f5f9;

    /* Elevation, focus, motion */
    --ds-shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.08);
    --ds-shadow-md: 0 10px 28px rgba(15, 23, 42, 0.12);
    --ds-focus-color: #2563eb;
    --ds-focus-ring: 0 0 0 3px rgba(37, 99, 235, 0.3);
    --ds-motion-fast: 120ms;
    --ds-motion-normal: 180ms;
    --ds-motion-easing: cubic-bezier(0.2, 0, 0, 1);
}

.ds-sr-only {
    position: absolute !important;
    width: 1px !important;
    height: 1px !important;
    padding: 0 !important;
    margin: -1px !important;
    overflow: hidden !important;
    clip: rect(0, 0, 0, 0) !important;
    clip-path: inset(50%) !important;
    white-space: nowrap !important;
    border: 0 !important;
}

.ds-heading,
.ds-body,
.ds-label,
.ds-code {
    font-family: var(--ds-font-sans);
}

.ds-heading {
    margin: 0;
    color: var(--ds-color-text);
    font-size: var(--ds-text-xl);
    font-weight: 800;
    line-height: var(--ds-leading-tight);
    letter-spacing: -0.02em;
}

.ds-body {
    color: var(--ds-color-text);
    font-size: var(--ds-text-md);
    line-height: var(--ds-leading-normal);
}

.ds-label {
    color: var(--ds-color-text-muted);
    font-size: var(--ds-text-xs);
    font-weight: 800;
    line-height: var(--ds-leading-normal);
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.ds-code {
    font-family: var(--ds-font-mono);
    font-variant-numeric: tabular-nums;
}

.ds-surface {
    color: var(--ds-color-text);
    background: var(--ds-color-surface);
    border: 1px solid var(--ds-color-border);
    border-radius: var(--ds-radius-lg);
    box-shadow: var(--ds-shadow-sm);
}

.ds-button {
    min-width: var(--ds-touch-target);
    min-height: var(--ds-touch-target);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--ds-space-2);
    padding: 0.625rem var(--ds-space-4);
    color: var(--ds-color-inverse);
    font-family: var(--ds-font-sans);
    font-size: var(--ds-text-sm);
    font-weight: 800;
    line-height: var(--ds-leading-tight);
    text-align: center;
    text-decoration: none;
    background: var(--ds-color-action);
    border: 2px solid transparent;
    border-radius: var(--ds-radius-md);
    box-shadow: var(--ds-shadow-sm);
    cursor: pointer;
    transition:
        background-color var(--ds-motion-fast) var(--ds-motion-easing),
        border-color var(--ds-motion-fast) var(--ds-motion-easing),
        box-shadow var(--ds-motion-fast) var(--ds-motion-easing),
        transform var(--ds-motion-fast) var(--ds-motion-easing);
}

.ds-button:hover:not(:disabled):not([aria-disabled="true"]) {
    background: var(--ds-color-action-hover);
}

.ds-button:active:not(:disabled):not([aria-disabled="true"]) {
    transform: translateY(1px);
}

.ds-button:focus-visible,
.ds-focusable:focus-visible {
    outline: 3px solid var(--ds-focus-color);
    outline-offset: 3px;
    box-shadow: var(--ds-focus-ring);
}

.ds-button:disabled,
.ds-button[aria-disabled="true"] {
    color: #64748b;
    background: #e2e8f0;
    border-color: #cbd5e1;
    box-shadow: none;
    cursor: not-allowed;
    opacity: 1;
}

.ds-button--secondary {
    color: var(--ds-color-text);
    background: var(--ds-color-surface);
    border-color: var(--ds-color-border-strong);
}

.ds-button--secondary:hover:not(:disabled):not([aria-disabled="true"]) {
    background: var(--ds-color-surface-muted);
}

.ds-button--danger {
    color: var(--ds-color-inverse);
    background: var(--ds-color-danger);
}

.ds-button--danger:hover:not(:disabled):not([aria-disabled="true"]) {
    background: var(--ds-color-danger-hover);
}

.ds-button--quiet {
    color: var(--ds-color-action);
    background: transparent;
    border-color: transparent;
    box-shadow: none;
}

.ds-button--quiet:hover:not(:disabled):not([aria-disabled="true"]) {
    color: var(--ds-color-action-hover);
    background: var(--ds-color-action-soft);
}

.ds-badge {
    --ds-badge-ink: var(--ds-color-unavailable);
    --ds-badge-surface: var(--ds-color-unavailable-soft);
    min-height: 1.625rem;
    display: inline-flex;
    align-items: center;
    gap: var(--ds-space-1);
    padding: 0.2rem 0.55rem;
    color: var(--ds-badge-ink);
    font-family: var(--ds-font-sans);
    font-size: var(--ds-text-xs);
    font-weight: 800;
    line-height: var(--ds-leading-tight);
    background: var(--ds-badge-surface);
    border: 1px solid currentColor;
    border-radius: 999px;
}

.ds-badge--info {
    --ds-badge-ink: var(--ds-color-info);
    --ds-badge-surface: var(--ds-color-info-soft);
}

.ds-badge--success {
    --ds-badge-ink: var(--ds-color-success);
    --ds-badge-surface: var(--ds-color-success-soft);
}

.ds-badge--warning {
    --ds-badge-ink: var(--ds-color-warning);
    --ds-badge-surface: var(--ds-color-warning-soft);
}

.ds-badge--danger {
    --ds-badge-ink: var(--ds-color-danger);
    --ds-badge-surface: var(--ds-color-danger-soft);
}

.ds-notice {
    --ds-notice-ink: var(--ds-color-info);
    --ds-notice-surface: var(--ds-color-info-soft);
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    align-items: start;
    gap: var(--ds-space-3);
    padding: var(--ds-space-4);
    color: var(--ds-color-text);
    font-family: var(--ds-font-sans);
    font-size: var(--ds-text-sm);
    line-height: var(--ds-leading-normal);
    background: var(--ds-notice-surface);
    border: 1px solid var(--ds-notice-ink);
    border-inline-start-width: 0.35rem;
    border-radius: var(--ds-radius-md);
}

.ds-notice strong,
.ds-notice__title {
    color: var(--ds-notice-ink);
    font-weight: 800;
}

.ds-notice--success {
    --ds-notice-ink: var(--ds-color-success);
    --ds-notice-surface: var(--ds-color-success-soft);
}

.ds-notice--warning {
    --ds-notice-ink: var(--ds-color-warning);
    --ds-notice-surface: var(--ds-color-warning-soft);
}

.ds-notice--danger {
    --ds-notice-ink: var(--ds-color-danger);
    --ds-notice-surface: var(--ds-color-danger-soft);
}

/* Use an inline SVG with aria-hidden="true" inside a labelled control. */
.ds-icon {
    width: 1.25rem;
    height: 1.25rem;
    flex: 0 0 auto;
    display: inline-block;
    color: currentColor;
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.ds-icon--status {
    width: 0.75rem;
    height: 0.75rem;
    fill: currentColor;
    stroke: none;
}

.ds-status {
    --ds-status-ink: var(--ds-color-unavailable);
    display: inline-flex;
    align-items: center;
    gap: var(--ds-space-2);
    color: var(--ds-status-ink);
    font-family: var(--ds-font-sans);
    font-size: var(--ds-text-sm);
    font-weight: 700;
}

.ds-status--info { --ds-status-ink: var(--ds-color-info); }
.ds-status--success { --ds-status-ink: var(--ds-color-success); }
.ds-status--warning { --ds-status-ink: var(--ds-color-warning); }
.ds-status--danger { --ds-status-ink: var(--ds-color-danger); }

/* Icons without adjacent text need an aria-label on their interactive parent. */
.ds-icon-button {
    width: var(--ds-touch-target);
    min-width: var(--ds-touch-target);
    height: var(--ds-touch-target);
    min-height: var(--ds-touch-target);
    padding: 0;
    border-radius: var(--ds-radius-md);
}

@media (prefers-reduced-motion: reduce) {
    :root {
        --ds-motion-fast: 0.01ms;
        --ds-motion-normal: 0.01ms;
    }

    .ds-button,
    .ds-focusable {
        scroll-behavior: auto !important;
        animation: none !important;
        transition-duration: 0.01ms !important;
        transition-delay: 0ms !important;
    }

    .ds-button:active:not(:disabled):not([aria-disabled="true"]) {
        transform: none;
    }
}

@media (forced-colors: active) {
    .ds-button,
    .ds-badge,
    .ds-notice,
    .ds-surface {
        border-color: CanvasText;
        forced-color-adjust: auto;
    }

    .ds-button:focus-visible,
    .ds-focusable:focus-visible {
        outline-color: Highlight;
        box-shadow: none;
    }
}