/* ============================================================
   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 is asking me to rewrite a CSS file with visual-only changes. 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;
    }
}
```

This is a media query with three rules. The original CSS is quite minimal — it doesn't have many colors, shadows, or radius values. Let me check what I'm allowed to change:

1. `.app-hero-section .row .col-lg-7` — has `text-align: center;` — text-align is in the NEVER CHANGE list (text-align, vertical-align). So I keep that.

2. `.app-hero-section .badge.bg-warning` — has `font-size: 0.85rem;` — font-size is in the NEVER CHANGE list. So keep that.

3. `.contact-channels-section article, .contact-quick-section .contact-card` — has `padding: var(--space-md) !important;` — padding can change within ±20%. But it uses a variable `--space-md`. I could change the variable value? The instruction says CSS custom properties (--color-*, --shadow-*) values can change. But `--space-md` is a spacing variable, not a color/shadow one. Hmm.

The problem is the original CSS is very minimal. There's almost nothing to change visually. The instructions say I MUST change colors, shadows, radius, transitions, gradients. But the original has none of those.

Since the target style is "sidebar-classic" with "tight-rhythm" variant, maybe I should add some visual properties that don't affect layout. However, I need to preserve selectors exactly and can only change visual properties.

Wait — I need to be careful. The HTML is fixed, and I can add visual properties as long as I don't change layout properties. Adding `box-shadow`, `border-radius`, `background-color`, etc. to existing rules is allowed? The task says "Refresh this CSS visually. Keep ALL selectors and layout exactly as-is. Only change colors, shadows, radius, transitions, gradients."

So I think I'm allowed to add visual properties to existing rules, as long as I don't change the existing layout properties. But the instruction also says "Every selector character-for-character preserved" and "display, position, grid-template-*, flex-direction unchanged" etc.

Since the original CSS is so sparse, the safest approach is to:
1. Keep all selectors
2. Keep all existing declarations (text-align, font-size, padding)
3. Add visual-only declarations (colors, shadows, border-radius, transitions) that don't affect layout

Wait, but should I add declarations that weren't there? The task says "Refresh this CSS visually" and lists what I must change. If there's nothing to change, I need to add something to fulfill the task.

Let me think about the padding change. `padding: var(--space-md) !important;` — padding is in the NEVER CHANGE list but with "keep similar values, ±20% maximum". Since it's a variable, I can't easily change it without changing the variable value. Actually, I could define `--space-md` differently? No, that would affect other things potentially, and it's a spacing variable.

Hmm, actually, maybe the intent is that the original CSS has more content and this is just a fragment. But the file fingerprint suggests this is the whole file.

Given the constraints, I'll:
- Keep text-align: center
- Keep font-size: 0.85rem
- Keep padding: var(--space-md) !important (since it's within ±20% if I keep the same variable)
- Add visual properties that are safe:

For `.app-hero-section .badge.bg-warning`:
- Add background-color, color, border-radius, box-shadow, transition — these are visual only.

For `.contact-channels-section article, .contact-quick-section .contact-card`:
- Add border-radius, box-shadow, background-color, border, transition — visual only.

For `.app-hero-section .row .col-lg-7`:
- text-align is layout-ish but it's listed as unchanged. I could add nothing to it or add a subtle text-shadow? text-shadow is allowed. But careful — text-align center is for the hero section, adding text-shadow might be okay.

Actually wait — the instructions say "All color values: background, color, border-color, fill, stroke, outline-color" must change. If the original has none, I should introduce them as new declarations? That seems to be the only way to fulfill "MUST CHANGE."

Let me reconsider. The target style is "sidebar-classic" — dark sidebar, light main. The "tight-rhythm" variant — compact spacing, small border-radius (2-6px), subtle shadows.

I'll apply these to the existing rules:

1. `.app-hero-section .row .col-lg-7` — I could add a `text-shadow` to make it a visual change, but text-align must remain center. Adding text-shadow is allowed (decorative). But it might affect readability. I'll add a subtle one.

Actually, wait — the original `.app-hero-section .row .col-lg-7` rule only centers text. Adding colors here might be risky because this could affect a lot of content. Let me be conservative and add minimal decorations.

2. `.app-hero-section .badge.bg-warning` — this is a warning badge. I can change `background-color`, `color`, `border-radius`, `box-shadow`, `transition`. But `.badge.bg-warning` is a Bootstrap class — the `bg-warning` sets a yellow background. If I override background-color here, it changes the badge color. That's visually significant. Let me pick a fresh palette: instead of the default Bootstrap warning yellow, use something like a warm amber with a new look.

3. `.contact-channels-section article, .contact-quick-section .contact-card` — cards. I can give them a new background, border-radius (2-6px per tight-rhythm), subtle shadow, and a transition.

Now, the padding: `padding: var(--space-md) !important;` — I'm not supposed to change it, but the instruction allows ±20% margin changes. Since I can't know the value of `--space-md`, I'll leave it as is. Actually, I could set a new value: `padding: calc(var(--space-md) * 0.9) !important;` to adjust within 20%? That's risky.

Better: keep the padding declaration exactly as-is. The instruction says "width, height, padding, margin within ±20% of input" — keeping it identical obviously satisfies that.

Let me plan the new CSS:

```css
@media (max-width: 575.98px) {
    .app-hero-section .row .col-lg-7 {
        text-align: center;
        text-shadow: 0 1px 2px rgba(37, 46, 58, 0.08);
    }

    .app-hero-section .badge.bg-warning {
        font-size: 0.85rem;
        background-color: #f0a03c;
        color: #252e3a;
        border: 1px solid rgba(37, 46, 58, 0.12);
        border-radius: 4px;
        box-shadow: 0 1px 3px rgba(37, 46, 58, 0.18);
        transition: background-color 0.2s ease, box-shadow 0.2s ease;
    }

    .contact-channels-section article,
    .contact-quick-section .contact-card {
        padding: var(--space-md) !important;
        background-color: #ffffff;
        border: 1px solid #e2e6ea;
        border-radius: 6px;
        box-shadow: 0 1px 2px rgba(37, 46, 58, 0.06);
        transition: box-shadow 0.2s ease, border-color 0.2s ease;
    }
}
```

Wait — the instruction says "border-color and border-style (NOT border-width)" can change. I'm adding a `border: 1px solid ...` declaration. But adding border-width could change layout! The original had no border. Adding a 1px border increases the element's size (unless box-sizing: border-box). That could affect layout. Hmm.

Actually, if the site uses `box-sizing: border-box` globally (Bootstrap does), adding a 1px border won't change the outer dimensions — it'll just take space from inside (reduce content box). Since padding is `var(--space-md)`, the border would be inside the padding area. This could be okay with border-box.

But to be really safe, since I don't know the box-sizing, maybe I should use `outline` instead of border? Outline doesn't affect layout at all. Or use `box-shadow` which also doesn't affect layout.

Hmm, but border-radius with outline doesn't clip. With border-radius, the background is clipped to the radius shape. If I add a border-radius and a background, the background will be clipped nicely. Adding a border is risky for layout.

Alternative approach: Use `box-shadow` for the border-like effect. Use `background-clip: padding-box` maybe.

Actually, Bootstrap 5 uses `box-sizing: border-box` globally, and `--space-md` is likely from Bootstrap's spacing scale. The classes `.badge.bg-warning` are Bootstrap classes. So border-box is safe. But I'm not 100% sure.

Let me think about what's minimal-risk yet satisfies the requirement:

For cards:
- `background-color` — changes visual, no layout impact
- `border-radius` — changes visual, no layout impact (with background it clips)
- `box-shadow` — changes visual, no layout impact
- `transition` — no layout impact
- `outline` — no layout impact, but border-radius doesn't clip outline
- `border: 1px solid ...` — layout impact only if content-box; with border-box, no outer size change

Since Bootstrap is mentioned (col-lg-7, badge, bg-warning), box-sizing: border-box is guaranteed. But padding is `!important`, and the border would add inside that. Actually, with border-box, width/height are fixed so border eats into padding space, making the padding slightly less effective visually. That's fine.

Also for the badge:
- `background-color`, `color`, `border-radius`, `box-shadow`, `transition` — all safe.
- Adding a border? The badge is an inline element typically; padding is set by Bootstrap. Adding a border might shift text slightly, but inline elements with border-box — hmm, inline elements don't necessarily have width/height, so border would add to their box. But it's a small shift and arguably a visual change.

Actually, the instructions say "border-color and border-style (NOT border-width)" may change. This implies there should be existing borders in the file. Since there are none, adding a border-width would be introducing something new. The prohibition is about not changing border-width of existing borders. Adding a new border is adding a new property, which is risky.

Let me be safe and avoid adding borders. Instead, use box-shadow to create a border-like effect: `box-shadow: 0 0 0 1px rgba(...)` — this creates a ring effect without affecting layout.

Also, the instruction says "outline styles (color, type)" can change. I could add `outline: 1px solid ...` — outline doesn't affect layout. But with border-radius, outline is not clipped (unless `outline-offset` negative... actually `outline` follows border-radius in modern browsers since Chrome 94). Hmm, outline follows the border-radius now. But outline taking focus ring... Adding outline might look weird. Better use box-shadow ring.

Let me reconsider — do I even need borders? The requirement: "Refresh this CSS visually. Keep ALL selectors and layout exactly as-is. Only change colors, shadows, radius, transitions, gradients." This gives me freedom to add colors, shadows, radius, transitions, gradients. It doesn't say I must add borders. So I'll skip borders entirely.

Plan:

```css
@media (max-width: 575.98px) {
    .app-hero-section .row .col-lg-7 {
        text-align: center;
        text-shadow: 0 1px 2px rgba(51, 65, 85, 0.06);
    }

    .app-hero-section .badge.bg-warning {
        font-size: 0.85rem;
        background-color: #e6a23c;
        color: #1f2937;
        border-radius: 4px;
        box-shadow: 0 2px 8px rgba(230, 162, 60, 0.28), inset 0 -1px 0 rgba(31, 41, 55, 0.12);
        transition: background-color 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
    }

    .contact-channels-section article,
    .contact-quick-section .contact-card {
        padding: var(--space-md) !important;
        background-color: #f8fafc;
        border-radius: 6px;
        box-shadow: 0 1px 2px rgba(15, 23, 42, 0.04), 0 4px 12px rgba(15, 23, 42, 0.03);
        transition: box-shadow 0.25s ease-in-out, background-color 0.25s ease-in-out;
    }
}
```

Hmm wait — for the badge, changing `background-color` on `.bg-warning` — Bootstrap's `.bg-warning` sets `background-color: #ffc107 !important;` Actually in Bootstrap 5, `.bg-warning` sets `--bs-bg-opacity: 1; background-color: rgba(var(--bs-warning-rgb), var(--bs-bg-opacity)) !important;`. Since the original rule sets only `font-size` with no `!important`, my new `background-color` (without `!important`) would NOT override Bootstrap's `!important` background. Hmm, that's a problem.

But the original rule didn't have `!important` on font-size either, and Bootstrap's `.badge` doesn't set font-size with `!important`, so `font-size: 0.85rem` works.

To override Bootstrap's `.bg-warning` background-color, I'd need `!important`. But adding `!important` isn't changing a forbidden property — it's fine. The original already uses `!important` on padding.

But wait — should I override the warning background? The instruction says color values must be replaced with fresh palette. Since original has no color, introducing new colors is fine. To actually take effect, I may need `!important` for background-color. Alternatively, I could use another property like `background-image: linear-gradient(...)` — but Bootstrap's background-color would still show through? No, background-image renders on top of background-color. But with gradients, I can change the visual. However, `.bg-warning` has no background-image, so adding one works without `!important`.

Simpler: Just add `background-color: ... !important;` to override Bootstrap. Or use both: a gradient background-image plus a background-color.

Also, in the "tight-rhythm" variant, border radius should be 2-6px. I picked 4px for badge and 6px for cards. Good.

Colors: The target palette says "Sidebar darker (#252e3a), main lighter, Functional accent for actions." The badge is like an accent/action. Let me use a fresh palette:

- Accent: a warm amber/copper: #d97729 or #e08a3c
- Dark: #252e3a
- Main background: #f7f9fb or #f8fafc
- Card background: #ffffff
- Shadow color: rgba(37, 46, 58, 0.08) etc.

Let me refine:

Badge:
- background: linear-gradient(135deg, #ed9e4a, #d97b29) maybe — a bit aggressive. Or just #e0933b.
- color: #252e3a (dark text on amber)
- border-radius: 4px
- box-shadow: 0 2px 6px rgba(37, 46, 58, 0.15)
- transition

Cards:
- background-color: #ffffff
- border-radius: 6px
- box-shadow: 0 1px 2px rgba(37, 46, 58, 0.05), 0 6px 16px rgba(37, 46, 58, 0.04)
- transition

Hero col:
- text-shadow: 0 1px 2px rgba(37, 46, 58, 0.06)

Now, about text-align: it's in the NEVER CHANGE list, so keep `text-align: center;`.

About font-size: keep `font-size: 0.85rem;`.

About padding: keep `padding: var(--space-md) !important;` exactly.

Now, one issue: adding `background-color: #ffffff` to `.contact-channels-section article, .contact-quick-section .contact-card` — what if those elements already have a background from another stylesheet? This rule is inside a media query for max-width 575.98px, so it only applies on small screens. Adding a background here will override any previous backgrounds on small screens. That's a visual change — intended.

But wait — `.contact-channels-section article` might be a general article and `.contact-card` might already have a background. Since the original rule only sets padding for small screens, the elements presumably have styling from elsewhere. When I add background-color here, it changes the small-screen appearance. That's exactly what "refresh visual identity" means.

Should I also add `background-color` without `!important`? If another rule sets background-color with higher specificity, mine might not apply. My selector `.contact-channels-section article`