/* ============================================================
   SAISHI.CSS v3.0 - 赛事/文章/APP 页面专属样式
   ============================================================
   匹配 Section 模板:
   - ArticleSection (单文章详情)
   - AppHeroSection / AppQrSection / AppInstallSection / AppShowcaseSection
   - ContactChannelsSection / ContactFormSection / ContactQuickSection / ContactCommitmentsSection
   - LoginFormSection / SignupFormSection
   - SearchBoxSection (extends)
   - 滚动条 / 打印样式 / 图标
   ============================================================ */

/* ============================================
   1. Single Post (ArticleSection)
   ============================================ */
.single-post {
    overflow: hidden;
}

.single-post .post-meta {
    font-size: 0.9rem;
}

.single-post .post-meta i {
    color: var(--color-primary);
}

/* Post content typography */
.post-content {
    line-height: 1.8;
    font-size: 1.05rem;
    color: var(--color-text);
}

.post-content :is(h2, h3, h4) {
    margin-block: 2rem 1rem;
    font-weight: 700;
    color: var(--color-primary-darker);
    line-height: 1.4;
}

.post-content h2 {
    font-size: 1.75rem;
    padding-bottom: var(--space-xs);
    border-bottom: 2px solid var(--color-border);
}

.post-content h3 {
    font-size: 1.35rem;
}

.post-content :is(p, li) {
    margin-bottom: var(--space-sm);
}

.post-content blockquote {
    border-inline-start: 4px solid var(--color-primary);
    padding: var(--space-sm) var(--space-md);
    background: var(--color-bg-soft);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    margin-block: var(--space-md);
    color: var(--color-text-muted);
    font-style: italic;
}

.post-content img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    margin-block: var(--space-sm);
    box-shadow: var(--shadow-sm);
}

.post-content a {
    color: var(--color-primary);
    text-decoration: underline;
    transition: color var(--transition-fast);
}

.post-content a:hover {
    color: var(--color-primary-dark);
}

.post-content ul,
.post-content ol {
    padding-inline-start: 1.5rem;
}

.post-content code {
    background: var(--color-bg-muted);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--color-danger);
}

.post-content pre {
    background: var(--color-primary-darker);
    color: #fff;
    padding: var(--space-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin-block: var(--space-md);
}

.post-content pre code {
    background: transparent;
    color: inherit;
    padding: 0;
}

.post-content table {
    width: 100%;
    border-collapse: collapse;
    margin-block: var(--space-md);
}

.post-content table th,
.post-content table td {
    padding: var(--space-xs) var(--space-sm);
    border: 1px solid var(--color-border);
    text-align: start;
}

.post-content table th {
    background: var(--color-bg-muted);
    font-weight: 600;
}

/* TOC */
.toc-box {
    border-inline-start: 3px solid var(--color-primary);
}

.toc-box ol {
    padding-inline-start: 1.2rem;
}

.toc-box ol li {
    margin: 0.4rem 0;
}

.toc-box ol li a {
    transition: all var(--transition-fast);
}

.toc-box ol li a:hover {
    color: var(--color-primary-dark);
    text-decoration: underline !important;
    padding-inline-start: 4px;
}

/* Tags */
.post-tags .badge {
    background: var(--color-bg-muted) !important;
    color: #475569 !important;
    padding: 6px 12px;
    font-weight: 500;
    transition: all var(--transition-fast);
}

.post-tags .badge:hover {
    background: var(--color-primary) !important;
    color: #fff !important;
    transform: translateY(-1px);
}

/* Post nav */
.post-nav {
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.post-nav .btn {
    max-width: 100%;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* ============================================
   2. App Hero (AppHeroSection)
   ============================================ */
.app-hero-section {
    background: var(--gradient-hero);
    color: #fff;
    position: relative;
    overflow: hidden;
}

.app-hero-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.2);
    z-index: 0;
}

.app-hero-section > .container {
    position: relative;
    z-index: 1;
}

.app-hero-section h1 {
    font-size: clamp(2rem, 4vw, 3rem);
    line-height: 1.2;
}

.app-hero-section img {
    transition: transform var(--transition-slow);
    filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.3));
}

.app-hero-section img:hover {
    transform: translateY(-10px);
}

.text-white-50 {
    color: rgba(255, 255, 255, 0.65) !important;
}

/* ============================================
   3. App QR (AppQrSection)
   ============================================ */
.app-qr-section {
    background: var(--color-bg-soft);
}

.qr-card {
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.qr-card:hover {
    transform: scale(1.03);
    border-color: var(--color-accent);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.qr-card img {
    image-rendering: pixelated;
    image-rendering: -moz-crisp-edges;
    image-rendering: crisp-edges;
}

/* ============================================
   4. App Install Steps (AppInstallSection)
   ============================================ */
.app-install-section {
    background: var(--color-bg-soft);
}

.app-install-section .badge.rounded-circle {
    width: 50px;
    height: 50px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 700;
}

.app-install-section .bg-white {
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.app-install-section .bg-white:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.app-install-section .bg-white::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--gradient-icon);
    transform: scaleY(0);
    transform-origin: top;
    transition: transform var(--transition-base);
}

.app-install-section .bg-white:hover::before {
    transform: scaleY(1);
}

/* ============================================
   5. App Showcase (AppShowcaseSection)
   ============================================ */
.app-showcase-section {
    background: var(--color-bg);
}

.app-showcase-section img {
    transition: transform var(--transition-slow);
    filter: drop-shadow(0 15px 30px rgba(0, 0, 0, 0.15));
}

.app-showcase-section img:hover {
    transform: translateY(-5px) rotate(-1deg);
}

.app-showcase-section .bg-white {
    transition: all var(--transition-base);
    border-inline-start: 3px solid transparent;
}

.app-showcase-section .bg-white:hover {
    border-inline-start-color: var(--color-primary);
    transform: translateX(5px);
    box-shadow: var(--shadow-md);
}

/* ============================================
   6. Contact Sections
   ============================================ */
.contact-channels-section {
    background: var(--color-bg);
}

.contact-channels-section article {
    transition: all var(--transition-base);
    border: 1px solid var(--color-border-soft);
}

.contact-channels-section article:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.contact-channels-section article ul li {
    transition: padding var(--transition-fast);
}

.contact-channels-section article ul li:hover {
    padding-inline-start: 4px;
}

/* Contact Quick */
.contact-quick-section {
    background: var(--color-bg-soft);
}

.contact-quick-section .contact-card {
    transition: all var(--transition-base);
}

.contact-quick-section .contact-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.contact-quick-section .contact-card i {
    transition: transform var(--transition-base);
}

.contact-quick-section .contact-card:hover i {
    transform: scale(1.1) rotate(-5deg);
}

/* Contact Form */
.contact-form-section {
    background: var(--color-bg-soft);
}

.contact-form-section .form-control,
.contact-form-section .form-select {
    border: 2px solid var(--color-border);
    transition: all var(--transition-fast);
}

.contact-form-section .form-control:focus,
.contact-form-section .form-select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 0.2rem rgba(59, 130, 246, 0.1);
}

.contact-form-section button[type="submit"] {
    transition: all var(--transition-base);
}

.contact-form-section button[type="submit"]:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-primary);
}

/* Contact Commitments */
.contact-commitments-section {
    background: var(--color-bg-soft);
}

.contact-commitments-section .bg-white {
    transition: all var(--transition-base);
    text-align: center;
}

.contact-commitments-section .bg-white:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.contact-commitments-section .bg-white i {
    transition: transform var(--transition-base);
}

.contact-commitments-section .bg-white:hover i {
    transform: scale(1.15);
}

/* ============================================
   7. Login / Signup Forms
   ============================================ */
main:has(> .container > .bg-white > form) .input-group-text {
    background-color: var(--color-bg-muted);
    border-color: var(--color-border);
    border-inline-end: none;
}

main:has(> .container > .bg-white > form) .input-group .form-control {
    border-inline-start: none;
}

main:has(> .container > .bg-white > form) .input-group:focus-within .input-group-text {
    border-color: var(--color-primary);
    background-color: #eff6ff;
}

main:has(> .container > .bg-white > form) .input-group:focus-within .form-control {
    border-color: var(--color-primary);
}

main:has(> .container > .bg-white > form) .form-check-input:checked {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
}

main:has(> .container > .bg-white > form) button[type="submit"] {
    transition: all var(--transition-base);
    font-weight: 600;
}

main:has(> .container > .bg-white > form) button[type="submit"]:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-primary);
}

/* ============================================
   8. Icons
   ============================================ */
.icon-img {
    max-width: 32px;
    max-height: 32px;
    object-fit: contain;
}

.icon-emoji {
    display: inline-block;
    line-height: 1;
}

/* ============================================
   9. Hero Buttons (đã có ở theme.css nhưng bổ sung thêm)
   ============================================ */
.hero-buttons .btn {
    transition: all var(--transition-base);
}

.hero-buttons .btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.hero-buttons .btn-warning {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
    color: var(--color-primary-darker);
    font-weight: 600;
}

.hero-buttons .btn-warning:hover {
    background-color: var(--color-accent-dark);
    border-color: var(--color-accent-dark);
}

.hero-buttons .btn-outline-light:hover {
    background-color: rgba(255, 255, 255, 0.15);
    color: #fff;
}

/* ============================================
   10. 自定义滚动条
   ============================================ */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg-muted);
}

::-webkit-scrollbar-thumb {
    background: #94a3b8;
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-text
-muted);
}

/* Firefox */
* {
    scrollbar-width: thin;
    scrollbar-color: #94a3b8 var(--color-bg-muted);
}

/* ============================================
   11. Print Styles
   ============================================ */
@media print {
    :is(.header,
        .footer,
        .sidebar-widgets,
        .social-share,
        #back-to-top,
        .breadcrumb-nav,
        .notice-bar,
        .cta-banner-section,
        .post-nav,
        .related-posts,
        .author-box,
        .pagination,
        .navbar-toggler,
        .nav-item) {
        display: none !important;
    }

    body {
        background: #fff !important;
        color: #000 !important;
        font-size: 12pt;
    }

    .single-post {
        box-shadow: none !important;
        border: none !important;
        padding: 0 !important;
        max-width: 100% !important;
    }

    .post-content {
        font-size: 11pt;
        line-height: 1.6;
    }

    a {
        text-decoration: underline;
        color: #000 !important;
    }

    a[href^="http"]::after {
        content: " (" attr(href) ")";
        font-size: 9pt;
        color: #555;
    }

    a[href^="#"]::after,
    a[href^="javascript:"]::after,
    a[href^="mailto:"]::after,
    a[href^="tel:"]::after {
        content: "";
    }

    .post-content img {
        max-width: 100% !important;
        page-break-inside: avoid;
    }

    :is(h1, h2, h3, h4) {
        page-break-after: avoid;
        color: #000 !important;
    }

    p, li {
        orphans: 3;
        widows: 3;
    }
}

/* ============================================
   12. Animations bổ sung
   ============================================ */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.animate-fade-in {
    animation: fadeInUp 0.6s ease-out;
}

.animate-pulse {
    animation: pulse 2s infinite;
}

/* ============================================
   13. Responsive
   ============================================ */
@media (max-width: 991.98px) {
    .post-content {
        font-size: 1rem;
    }

    .post-content h2 {
        font-size: 1.5rem;
    }

    .post-content h3 {
        font-size: 1.2rem;
    }
}

@media (max-width: 767.98px) {
    .single-post {
        padding: var(--space-md) !important;
    }

    .post-content {
        font-size: 0.95rem;
    }

    .post-content h2 {
        font-size: 1.35rem;
    }

    .post-nav {
        flex-direction: column;
    }

    .post-nav .btn {
        width: 100%;
    }

    .post-tags .badge {
        font-size: 0.8rem;
        padding: 4px 8px;
    }

    .app-hero-section h1 {
        font-size: 1.75rem;
    }

    .app-install-section .badge.rounded-circle {
        width: 40px;
        height: 40px;
        font-size: 1rem;
    }

    .toc-box {
        padding: var(--space-sm) !important;
    }

    .qr-card img {
        max-width: 140px !important;
    }
}

The user wants me to rewrite the CSS with a new visual identity while keeping all selectors and layout properties intact. Let me analyze the original CSS:

```css
@media (max-width: 575.98px) {
    .app-hero-section .row .col-lg-7 {
        text-align: center;
    }

    .app-hero-section .badge.bg-warning {
        font-size: 0.85rem;
    }

    .contact-channels-section article,
    .contact-quick-section .contact-card {
        padding: var(--space-md) !important;
    }
}
```

Wait, this is only a media query block. The task says to refresh the visual identity. But there are constraints:

- text-align: center — this is a layout property? Actually text-align is listed under "📐 LAYOUT" as "text-align, vertical-align" — so I must NOT change it.
- font-size: 0.85rem — typography, must NOT change.
- padding: var(--space-md) !important — padding is layout, but can I change the value? The constraint says "padding, margin (keep similar values, ±20% maximum)". Since it uses a CSS variable `--space-md`, I could potentially change the variable value if defined, but it's not defined in this snippet. Changing the variable name would break layout. I should keep it as-is or adjust within ±20%. Since it's a var reference, I can't easily adjust by 20% without knowing the value. Safest: keep it.

But the task is to refresh colors, shadows, radius, transitions, gradients. The original CSS has none of those properties except text-align, font-size, and padding. There are no colors, no shadows, no border-radius, no transitions, no gradients in this media query block.

Hmm. So what can I do? The instruction says "Only change colors, shadows, radius, transitions, gradients." But there are none to change here.

However, there is a mention of `bg-warning` class — that's a Bootstrap class, but the CSS doesn't define its styles here.

Given the constraints, I might be able to:

1. Add custom properties? No, the task says "CSS custom properties (--color-*, --shadow-*) values" can change. But there are none here except `--space-md` used in padding.

2. Add new visual declarations? The task says "Refresh the CSS visually. Keep ALL selectors and layout exactly as-is. Only change colors, shadows, radius, transitions, gradients." This could be interpreted as: I can add visual-only properties to the existing selectors, or change existing ones. But the original CSS doesn't have any visual properties.

Actually, looking more carefully at the instructions: "You MUST CHANGE (visual identity only): All color values, background, color, border-color, fill, stroke, outline-color, box-shadow, text-shadow, border-radius, gradient colors and stops, transition timing/easing/duration, filter, backdrop-filter, opacity, outline styles, border-color and border-style, caret-color, accent-color, CSS custom properties."

So the idea is that when the CSS has such values, I must change them. When it doesn't, I guess I can add some? But that could break things... Actually adding visual-only properties like color, background, border-radius, box-shadow, transition to these selectors wouldn't break layout. But it would change the appearance — which is the point.

However, the instruction also says "NEVER CHANGE" includes selectors, layout, typography. And "padding, margin (keep similar values, ±20% maximum)". The original has `padding: var(--space-md) !important;`. I could change it within ±20% — but it's a var reference. I could perhaps change it to a slightly different value? The rule says "keep similar values, ±20% maximum". So I could change `var(--space-md)` to a specific value that is roughly similar? That's risky because I don't know what `--space-md` resolves to.

Alternatively, I could add a `transition` and maybe an `opacity`? No, those would be adding new properties not originally present. The task says "Refresh the CSS visually" — but if I add color/background to `.app-hero-section .row .col-lg-7`, that changes appearance heavily and might not be desired. But the target style is "dense-dashboard" with white cards on slate background.

Hmm. Let me re-read the task instructions carefully.

The user gave me a chunk of CSS (labeled "#块2/2" meaning block 2 of 2 from file `assets/css/saishi.css`). The request ID and fingerprint suggest this is part of a larger file. Only this block is shown. The block is a media query for small screens.

I need to output the rewritten CSS for this block only. The original has:

- `text-align: center` (layout - keep)
- `font-size: 0.85rem` (typography - keep)
- `padding: var(--space-md) !important` (layout - keep similar)

There are no color, shadow, radius, transition, gradient, opacity, filter, etc. properties present.

So the "conservative" approach: since there is nothing visual to change, the safest rewrite is to output the same CSS. But the task explicitly says "Refresh this CSS visually" and "Only change colors, shadows, radius, transitions, gradients."

Wait — maybe I can add visual properties to these selectors. The instruction says I MUST change visual properties, but when none exist, adding them could fulfill the spirit of the task. But that's dangerous because:

1. `.app-hero-section .row .col-lg-7` is a column with text. Adding color would change text color.
2. `.app-hero-section .badge.bg-warning` is a Bootstrap warning badge. The class `bg-warning` has a Bootstrap background. I could override it with a `background-color` and `color`, plus maybe a `border-radius`? But the rule says "NEVER CHANGE ... border-style (NOT border-width)" — wait, border-radius is allowed. But adding background-color changes the badge look.

Hmm, but the target style says "White cards on slate background", "Small border-radius (2-6px)", "Subtle shadows or none". 

Actually, let me reconsider. The media query is a small-screen override. The original sets:
- Center text in hero column
- Font size of badge 0.85rem
- Padding of contact cards to --space-md

Given the target style "dense-dashboard" and "tight-rhythm", the changes I could make within the rules:

1. For `.app-hero-section .row .col-lg-7`: keep `text-align: center;` — no visual properties to change. Could add nothing.
2. For `.app-hero-section .badge.bg-warning`: keep `font-size: 0.85rem;`. I could add color/background? But no original color exists. Adding might be acceptable?
3. For `.contact-channels-section article, .contact-quick-section .contact-card`: keep padding. The padding uses `var(--space-md)`. I could maybe adjust? No, keep it.

The strict, conservative interpretation: output the exact same CSS because there's nothing to change without breaking the "only change visual properties" rule. But that seems like a failed task.

Let me look at the original rules again:

"✅ YOU MUST CHANGE (visual identity only):" — lists properties that must be changed IF PRESENT.

"🔒 NEVER CHANGE (would break HTML layout):" — includes padding/margin with ±20%. text-align is under layout too.

So the directive is: change the visual properties present in the file. If none are present, then there's nothing to change related to those. However, the user prompt says "Refresh this CSS visually." 

Could I add `transition`? The target style says "Subtle shadows or none" — maybe I could add a subtle `box-shadow` to the contact cards? But the contact cards in the original media query only set padding. Adding `box-shadow` to them would be a visual change — but is it a "change" or an "addition"? The task says "Only change colors, shadows, radius, transitions, gradients." It doesn't say "add" these. But if a property doesn't exist, you can't "change" it. 

Hmm, but there's the "OUTPUT" section: "rewritten CSS, preserving ALL selectors and layout exactly". The rewritten CSS should reflect a fresh visual identity. 

Given the "dense-dashboard" / "tight-rhythm" target, maybe I can:

- For the badge: since it's `.bg-warning`, I can override its background and color to fit the new palette. For example, instead of Bootstrap yellow, make it a slate/dark badge with blue accent? But `.bg-warning` in Bootstrap is `background-color: #ffc107`. Overriding it in this media query with `background-color: #3b82f6` (accent blue) and `color: #fff` would make it visually consistent. That's a legitimate visual identity change. But does the original have a `color` property? No. Adding one is fine because it's a visual-only property. And `background-color` is in the ✅ list. 

- For the contact cards: keep padding, but maybe add a subtle box-shadow? Border-radius? That would align with "subtle shadows or none" and "small border-radius (2-6px)". But adding box-shadow to `.contact-card` inside a media query would change appearance on mobile only. Hmm. But the target "white cards on slate background" — I could give the cards a white background and subtle shadow. But wait, the original media query only sets padding. The base styles (outside this block) probably set backgrounds. If I add a background color here, it might conflict. But it's a "visual identity" refresh, so overriding is fine.

However, the instructions say "Keep ALL selectors and layout exactly as-is." and "ONLY the rewritten CSS, preserving ALL selectors and layout exactly". Adding new declarations to existing selectors preserves selectors and layout. The risk is changing the look more than intended, but that's the point of a visual refresh.

But hold on — there's a subtle issue: The original CSS block is `@media (max-width: 575.98px) { ... }`. The instruction says "animation-name (values like duration/timing CAN change)" and "@media query breakpoints (conditions only)" — so the media query condition `(max-width: 575.98px)` must stay exactly.

Also, the selector list `.contact-channels-section article, .contact-quick-section .contact-card` has a comma — must keep exactly.

Let me decide: I'll add a few visual declarations that match the target style, while keeping all original declarations unchanged:

1. `.app-hero-section .row .col-lg-7`: keep `text-align: center;`. Maybe add nothing else? Adding a `color` could be risky. But the target palette is cool grays #1e293b, #334155, accent blue #3b82f6, white cards on slate. The hero text color might already be set elsewhere. If I add `color: #334155`, it might override. Since this is a mobile media query, that could be fine. But to be conservative, I could skip adding anything here, or add a subtle `text-shadow`? No, adding text-shadow to hero text might look odd. 

2. `.app-hero-section .badge.bg-warning`: keep `font-size: 0.85rem;`. Add a visual refresh: `background-color: #3b82f6; color: #ffffff;` and maybe `border-radius: 4px;`? Wait, `border-radius` is in the ✅ list. But Bootstrap badge already has a border-radius. Changing it in the media query to a smaller radius (2-6px) fits "tight-rhythm". Also add `box-shadow: 0 1px 2px rgba(30, 41, 59, 0.4);` for a subtle shadow — but the variant says "subtle shadows or none". That could be fine.

Hmm, but is it appropriate to turn a warning badge blue? The class name is `bg-warning`, but the visual identity refresh can change colors. The target palette emphasizes blue accents. So yes.

3. `.contact-channels-section article, .contact-quick-section .contact-card`: keep `padding: var(--space-md) !important;`. Add `border-radius: 4px;` maybe? And `background-color: #ffffff;` plus a subtle shadow? But wait — the original only sets padding. If I set background-color to white, it might override a slate background. The target style says "White cards on slate background". So that could be exactly right: cards become white with a subtle shadow and small radius.

But be careful: `article` elements under `.contact-channels-section` — are they cards? Likely yes. So making them white cards fits.

Let me add:

```css
@media (max-width: 575.98px) {
    .app-hero-section .row .col-lg-7 {
        text-align: center;
    }

    .app-hero-section .badge.bg-warning {
        font-size: 0.85rem;
        background-color: #3b82f6;
        color: #ffffff;
        border-radius: 4px;
        box-shadow: 0 1px 2px rgba(30, 41, 59, 0.4);
    }

    .contact-channels-section article,
    .contact-quick-section .contact-card {
        padding: var(--space-md) !important;
        background-color: #ffffff;
        border-radius: 4px;
        box-shadow: 0 1px 3px rgba(30, 41, 59, 0.12);
        transition: box-shadow 0.2s ease-in-out;
    }
}
```

Wait, but the instruction says "transition timing, easing, duration" must change if present. Since none present, adding one is optional. Adding a transition to cards is a visual enhancement. But it doesn't have a hover state here, so a transition without a hover does nothing. Still fine.

However, I'm worried about the "±20%" rule for padding. `padding: var(--space-md)` stays exactly as-is. Good.

Also, the variant says "Small border-radius (2-6px)" — 4px fits. "Subtle shadows or none" — 0 1px 2px / 0 1px 3px are subtle. Good.

But there's a concern: The user said "only change colors, shadows, radius, transitions, gradients." I'm adding `background-color`, `color`, `border-radius`, `box-shadow`, `transition` — all in the allowed list. Good.

But am I allowed to add properties that weren't there? The instruction "You MUST CHANGE" lists visual properties; it doesn't forbid adding them. And "Refresh this CSS visually" implies making visible changes. So yes.

Alternatively, a more conservative output: just return the same CSS unchanged because there are no visual properties to change. But that fails the task's spirit.

Let me also consider: maybe the `@media` block is only a portion of the file, and the rest of the file (block 1) contains the main styles. The user is asking to process this block. The instructions mention "File: assets/css/saishi.css#块2/2" — block 2 of 2. So perhaps the previous block had the main styles and this block is the responsive part. Since the main styles are not shown, I can only work with what's here.

Given that, adding visual declarations here is the way to fulfill the "refresh" mission.

But wait — should I add a `background` to `.app-hero-section .row .col-lg-7`? No, that's a column, not a card. Adding a background could make the hero section look like a card. The target says "white cards on slate background" — maybe the hero could become a card? But that might drastically change the mobile layout. Actually, since the column contains text and a badge, adding a background to the column could look like a banner. Hmm. Risky.

Better to keep `.app-hero-section .row .col-lg-7` unchanged (only text-align), because there's no visual property to change there. But the task says refresh all? No, it says refresh the visual identity of the CSS. If a selector has no visual properties, I can leave it. But to show a consistent effort, maybe I could add a slight enhancement. Let me think.

Actually, re-reading the rule: "✅ YOU MUST CHANGE (visual identity only): All color values, background, color, border-color, fill, stroke, outline-color, box-shadow, text-shadow, border-radius, gradient colors and stops in linear/radial/conic-gradient, transition timing, easing, duration, filter, backdrop-filter, opacity, outline styles (color, type), border-color and border-style (NOT border-width), caret-color, accent-color, CSS custom properties (--color-*, --shadow-*) values."

So the rule applies to values that exist in the input. If there are no color values, then there's nothing to change. The instruction is about changing existing values, not necessarily adding new ones.

But the target style description says "Aggressive only" — that's an internal note (the mode is Conservative, but the target style template says "Layout pattern (Aggressive only)" — that's probably a mistake in the template; the mode is 🛡️ CONSERVATIVE). The variant "tight-rhythm" says compact spacing, small border-radius, subtle shadows.

Given the conservative mode, I should be careful. But adding new property declarations to existing selectors doesn't violate any "NEVER CHANGE" rule. It's within scope.

However, there's a risk: If I add `background-color: #ffffff` to `.contact-channels-section article`, and the base style already gives it a color, this media query might override it only on mobile. That could be intentional for the visual refresh.

Hmm, but the instruction says "HTML is FIXED — only colors, shadows, and decorative properties may change." Adding decorative properties is allowed.

Let me finalize my approach:

- Keep all original declarations verbatim.
- Add visual-only declarations that match the target palette and variant:
  - Badge: `background-color: #3b82f6; color: #fff; border-radius: 4px; box-shadow: