/* ============================================================
   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 in a "card-mosaic" style with "soft-shadows" variant. But looking at the original CSS, it's just a small media query with a few rules. There's no actual grid or card layout here — it's a responsive adjustment for an app hero section and contact sections.

Let me analyze what's in 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;
    }
}
```

The constraints say:
- Selectors must be preserved exactly
- Layout properties (display, position, grid, width, height, padding, margin) cannot change
- Typography (font-size, font-weight, line-height, text-align) cannot change
- Only colors, shadows, radius, transitions, gradients, opacity, etc. can change

Wait, but `text-align: center` and `font-size: 0.85rem` are typography/layout — those are in the "never change" list:
- font-size, font-weight, font-style — cannot change
- text-align, vertical-align — cannot change

And `padding: var(--space-md) !important` — padding is in the layout section, but with ±20% tolerance. However, this uses a CSS variable `--space-md` which is a custom property value... but changing the custom property value would affect the padding. The padding rule itself must stay. Actually, the instruction says "padding, margin (keep similar values, ±20% maximum)" — but `var(--space-md)` is a variable reference. I could change the `--space-md` variable value, but that's not defined in this file. So I should leave the padding rule as-is.

What CAN I change here?
- The media query itself: conditions only — breakpoints must stay. `@media (max-width: 575.98px)` — that's the condition, keep it.
- `.app-hero-section .badge.bg-warning` — has `font-size: 0.85rem` — typography, can't change. Nothing else in the rule.
- `.contact-channels-section article, .contact-quick-section .contact-card` — padding, can't change (or within ±20%, but with var() I can't compute).

Hmm, this is tricky. The original CSS block has almost no visual properties I'm allowed to change. The only things I could add are:
- box-shadow
- border-radius
- transition
- color/background (but there are none)
- backdrop-filter
- etc.

Wait — the task says "Refresh this CSS visually. Keep ALL selectors and layout exactly as-is. Only change colors, shadows, radius, transitions, gradients." It says I can add decorative properties as long as I don't change layout. But the rules say "You MUST change: All color values, box-shadow, text-shadow, border-radius..." — but there are none in this file.

The self-check says:
- "Colors throughout the file replaced with fresh palette?" — there are no colors to replace.
- "Shadows redesigned?" — there are none.
- "Border-radius adjusted?" — none.

So the honest approach: since the original CSS has only typography/layout rules that I'm forbidden from changing, the rewritten CSS should be nearly identical. However, I could ADD decorative properties (box-shadow, border-radius, transition, background) to the existing selectors to achieve the visual refresh without changing any layout properties.

Actually, let me re-read: "Only change colors, shadows, radius, transitions, gradients." This implies I can add these properties to rules that didn't have them. Adding properties doesn't violate "keep selectors and layout exactly as-is" — I'm not changing any existing layout properties, just augmenting with decorative ones.

Let me think about the target style: "card-mosaic" with "soft-shadows":
- Multi-layer soft shadows: `0 4px 8px rgba(0,0,0,0.05), 0 20px 40px -10px rgba(0,0,0,0.12)`
- Large border-radius (12-24px)
- Smooth transitions (0.3-0.5s ease)

The elements involved:
1. `.app-hero-section .badge.bg-warning` — a badge (warning color)
2. `.contact-channels-section article` — contact channel cards
3. `.contact-quick-section .contact-card` — contact quick cards

These are card-like elements (articles, contact cards). I can give them border-radius, box-shadow, and transitions. The badge could get a subtle shadow and radius too.

But wait — adding `border-radius` to `.contact-card` and `article` changes their visual but not layout. Adding `box-shadow` doesn't affect layout. Adding `transition` doesn't affect layout. Adding `background` could be risky (might cover content or change appearance), but vibrant card colors are part of the target style. However, changing background-color on elements that might have backgrounds already could be risky. Since the original CSS doesn't specify backgrounds, the elements inherit from elsewhere. Adding background-color would override — that's a color change, allowed on the "must change" list. But I need to be careful because these elements might contain text with specific contrast.

Hmm, but actually — the goal says "vibrant card colors on neutral background. Each card type a different accent." But this is a media query for small screens (max-width: 575.98px). Adding colorful backgrounds to contact cards at mobile could be a legitimate visual refresh.

But I must be careful not to break the layout. Adding background doesn't break layout. Adding padding would, but I won't.

Let me also consider: the rule `.app-hero-section .row .col-lg-7 { text-align: center; }` — text-align is typography/layout, I must keep it. I could add nothing decorative here, or maybe add nothing. Actually, I shouldn't add shadows/backgrounds to a text-align rule — the col is a container; adding a shadow to it would be weird and could change the visual drastically. But the task says only colors/shadows/radius/transitions/gradients may change. I think it's acceptable to add a transition or subtle properties where sensible, but for the hero column, there's nothing to decorate. I'll keep it as-is.

For `.app-hero-section .badge.bg-warning` — I can add a soft shadow, border-radius (badges often have pill radius), and maybe a gradient background. But `bg-warning` is a Bootstrap class. If I add `background: linear-gradient(...)` to `.badge.bg-warning`, I'd override Bootstrap's warning background. That's a color change — allowed. But would it break anything? The badge text is likely dark (warning is yellow/orange). If I change the background to a vibrant gradient, I should keep text readable. I could keep it in the warm/orange spectrum.

Wait — but there's a subtlety. The selector is `.app-hero-section .badge.bg-warning` within the media query. If I add a background gradient there, it'll only apply on mobile. That's fine.

Actually, let me reconsider the scope. The task says "Refresh this CSS visually" — but the file is a fragment (块2/2 — block 2 of 2). It's a media query block. In conservative mode, my job is to produce a visually refreshed version. The most defensible approach:

1. Keep `.app-hero-section .row .col-lg-7 { text-align: center; }` exactly — nothing to change; maybe add nothing. But wait, the instructions say "You MUST change: All color values..." — but there are no color values. The self-check says "Colors throughout the file replaced with fresh palette?" — if there are none, this is vacuously true.

2. For the badge: add soft shadow, rounded radius, maybe a warm gradient. But changing `background` via gradient would override Bootstrap's `bg-warning`. I'll do a gradient that stays in the amber/warning family: something like `linear-gradient(135deg, #ffd166, #f4a261)` with a subtle shadow. And `border-radius: 0.75rem` (12px) — though badges are usually pills with `--bs-badge-border-radius`. Setting a custom radius is fine. Add `transition: all 0.4s ease`. But hover states aren't in the media query — I shouldn't add :hover selectors (the rules say pseudo-classes must be kept exactly, meaning I can't add new ones). So just the base transition, no hover needed.

Wait, actually adding a transition without a hover does nothing unless the element changes state somehow. But it's still a "visual identity" property. I could add `transition` to the contact cards for when they're interacted with elsewhere, but there's no hover rule here. Still, adding transitions is allowed.

3. For the contact cards (`.contact-channels-section article, .contact-quick-section .contact-card`): add multi-layer soft shadows, large border-radius (16-20px), smooth transitions, and maybe "vibrant card colors on neutral background" — but adding background colors to these cards would be a big visual change. Since the target style says "Vibrant card colors on neutral background — Each card type a different accent", I can add:
   - `.contact-channels-section article` — one accent background (e.g., a soft gradient)
   - `.contact-quick-section .contact-card` — another accent

But hold on — the padding is `var(--space-md) !important`. That stays. Adding a background is fine. But if these cards already have a background from the base CSS (outside this file), adding a new one here will override within the media query — on mobile only. That could be a jarring break between mobile and desktop. But the task explicitly wants a visual refresh, so this is acceptable.

However, I need to be careful: if the original card has a white background and I change it to a vibrant color, the text inside (likely dark gray) might become unreadable. Since I don't know the text color, choosing vibrant dark-ish accents might keep contrast. Or I could use very soft tinted backgrounds (like pale tints) which are safer. The palette says "vibrant card colors on neutral background" — but I could interpret: the background of each card type is a different accent. Let me pick colors that are vibrant but not too dark, and ensure text contrast by keeping the card background light-ish or medium.

Actually, a safer approach for "card-mosaic" + "soft-shadows": keep the cards light/neutral (white or very light tint) and add a colored accent via box-shadow or a subtle gradient. But the target style explicitly says "Vibrant card colors on neutral background. Each card type a different accent."

Hmm, the target style is labeled "(Aggressive only)" — meaning the layout pattern (grid with mixed spans) is aggressive mode. In conservative mode, I can't change the grid. The color palette and effect variant are what I should apply. So I should apply vibrant card colors as much as conservative mode allows.

In conservative mode, I can change background colors freely. Let me do it thoughtfully:

- `.contact-channels-section article` — vibrant accent card. Let's say a coral/peach gradient: `linear-gradient(135deg, #ff6b6b, #ff8e53)` — but text inside might be white... I don't know. Risk. Alternatively, a very soft gradient with a colored border/glow. But I shouldn't add border-width. Can I add border? The rules say "border-color and border-style (NOT border-width)" can change. Adding a border property with a width not present... the original has no border. Adding `border: 2px solid ...` would change border-width from 0 to 2px — is that a layout change? Border-width affects box size unless box-sizing: border-box. The rules say don't change border-width. So I should not add borders. Only change existing border-color/border-style. So no new borders.

OK so background gradient + box-shadow + border-radius + transition is the toolkit.

Let me think about contrast. The `article` elements in `.contact-channels-section` — contact channel cards. They might contain an icon and text. If I set a vibrant background, text color is unknown. To be safe, I'll use vibrant gradient backgrounds but keep them on the lighter side, or use a white card with a colored shadow... but "vibrant card colors" — hmm.

Actually, re-reading the effect variant: "Multi-layer soft shadows: 0 4px 8px rgba(0,0,0,0.05), 0 20px 40px -10px rgba(0,0,0,0.12). Large border-radius (12-24px). Smooth transitions (0.3-0.5s ease)." These are the primary required effects. The color palette says "vibrant card colors on neutral background" — I can apply that to the hero badge too.

Let me go with:
- `.app-hero-section .badge.bg-warning`: warm amber gradient `linear-gradient(135deg, #ffb703, #fb8500)`, soft shadow `0 4px 12px rgba(251, 133, 0, 0.35)`, border-radius 0.75rem, transition. The badge text is likely dark (Bootstrap warning uses dark text via `--bs-warning-rgb` with color-mix). Overriding the background with a similar orange keeps it readable.

- `.contact-channels-section article`: a soft teal/blue or coral card. Let me pick a vibrant but not too dark accent. Since these are "channels" (like chat, email, phone), I'll do a linear gradient in cool hues. But text inside could be dark. If I set `background: linear-gradient(135deg, #4facfe, #00f2fe)` the text (probably dark or white?) — unknown. 

Hmm. Honestly, without seeing the HTML, adding vibrant backgrounds is risky. Let me reconsider: maybe a more conservative interpretation is to add soft tinted backgrounds. "Vibrant" though... The palette says "Vibrant card colors on neutral background. Each card type a different accent."

Alternative: Use background gradients that are vibrant but include a semi-transparent layer, or use solid vibrant colors that work with white text. Many marketing sites use white text on vibrant cards. But if this is a Bootstrap site, the card text is probably `var(--bs-body-color)` (dark). If I set a vibrant mid-tone background, dark text might still be readable if the tone is light enough. 

Let me choose medium-light vibrant tones:
- Channel cards: `linear-gradient(135deg, #a18cd1, #fbc2eb)` — lavender to pink, light enough for dark text.
- Contact quick cards: `linear-gradient(135deg, #84fab0, #8fd3f4)` — mint to sky, light enough for dark text.
- Badge: `linear-gradient(135deg, #ffd166, #ff9f1c)` — amber, dark text readable.

These are vibrant yet pastel enough for dark text. They match "card-mosaic" (each card type different accent).

Actually wait — should I even add gradients to elements that might already have backgrounds? The `.contact-quick-section .contact-card` might have a background defined elsewhere. Overriding in this media query only affects mobile (<576px). That's fine for a refresh.

One concern: The instruction says "padding: var(--space-md) !important" — that stays. With a background added, the padding applies to the card, good.

Another thought: The `.app-hero-section .row .col-lg-7` rule — nothing to change. It's a text-align center. I'll leave it as-is. Technically I could add a transition, but it's meaningless. Keep it clean.

Actually, should I add `border-radius` to `.app-hero-section .row .col-lg-7`? It's a column — adding radius without background/border does nothing visible. Skip.

What about adding `backdrop-filter`? Not needed.

Now, the padding rule with `!important` — I must preserve exactly: `padding: var(--space-md) !important;`. Yes.

Let me draft:

```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: linear-gradient(135deg, #ffd166, #ff9f1c);
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05), 0 20px 40px -10px rgba(251, 133, 0, 0.25);
        border-radius: 0.75rem;
        transition: all 0.4s ease;
    }

    .contact-channels-section article,
    .contact-quick-section .contact-card {
        padding: var(--space-md) !important;
        border-radius: 1.25rem;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05), 0 20px 40px -10px rgba(0, 0, 0, 0.12);
        transition: transform 0.4s ease, box-shadow 0.4s ease;
    }

    .contact-channels-section article {
        background: linear-gradient(135deg, #a18cd1, #fbc2eb);
    }

    .contact-quick-section .contact-card {
        background: linear-gradient(135deg, #84fab0, #8fd3f4);
    }
}
```

Wait — but I'm adding new rules `.contact-channels-section article { ... }` and `.contact-quick-section .contact-card { ... }` separately after the grouped rule. Is that allowed? The selector `.contact-channels-section article` already exists in the grouped rule. I'm reusing the same selector in a new rule. The rule "Selectors: keep EXACTLY