/* ============================================================
   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;
    }
}

We need answer CSS only. Need rewrite visually. Need obey constraints. Original CSS only media query with few rules. There are no colors etc. Need perhaps add visual properties? But cannot change selectors, layout. We can adjust only colors, shadows, radius etc. Since original has none, can add? Need "Refresh visual identity WITHOUT changing layout structure or class names." Original only text-align and font-size and padding. We must preserve those? Layout includes text-align? It says typography font-size etc cannot change. So we must keep font-size and text-align. padding is layout but says keep similar ±20% maximum. Padding in original: var(--space-md) !important. We can change? It says padding/margin keep similar ±20%. if variable not in file? Need maybe keep as is or calculate? Better keep padding same, no change. But target style tight-rhythm compact spacing might reduce padding? But conservative says keep similar. So maybe keep. Visual changes can include color additions? But selectors not originally color. We can add color, background, border-radius, box-shadow. Need not change layout. This will be fresh palette. Need output CSS with same selectors, same declarations plus new visual properties. But original rule includes .app-hero-section .row .col-lg-7 text-align center. That's layout? text-align is layout not to change. Keep exact.

Need adhere "Every selector character-for-character preserved?" yes.

Need consider media query conditions cannot change. Keep @media (max-width: 575.98px). Need maybe add color properties to existing selectors and perhaps add new rules? Would that violate? It didn't include more selectors; we can add selectors? All selectors need preserved, but may add? The task says CSS file #块2/2 only this. We should not add new rules? "ONLY the rewritten CSS, preserving ALL selectors and layout exactly" Could add visual declarations to existing selectors. Don't add extra rules maybe.

Need output no markdown. We can include declarations. Need ensure not changing padding. Original:
.app-hero-section .badge.bg-warning { font-size: 0.85rem; }
Could add background, color, border-radius, box-shadow? Since badge warning likely uses Bootstrap bg-warning, changing background to custom may override. Since "badge.bg-warning" with class .bg-warning but custom background added maybe okay. Need visual fresh. Could reset? We need color palette from target: sidebar darker #252e3a, main lighter, accent. In mobile context maybe apply to hero? Need use accent color. But careful not to alter layout. Could add decorative border-left? no, not asked and could position? It could affect layout if box-sizing? border? border-width not change? Border-style can change. But adding border may affect box sizing? Usually box-sizing may not be set. Better avoid border to not alter dimensions. Use box-shadow maybe no layout. Use color/background, border-radius. On badge, border-radius visual.

Need maybe change padding? Keep var(--space-md), maybe it's okay.

Need maybe include CSS custom properties? Not needed.

Need include transitions? Could add transition to visual properties. Fine.

Need ensure "No AI-REWRITTEN comments" no comments. Output.

But let's think: User says "Previous attempt didn't change enough. Make colors, shadows, and radius MORE distinct this round. Use a fresh palette." Original CSS lacks colors. Must add. Need perhaps "tight-rhythm" and "sidebar-classic" palette. 
Possible output:
@media (max-width: 575.98px) {
    .app-hero-section .row .col-lg-7 {
        text-align: center;
        color: #252e3a;
        background: linear-gradient(180deg, rgba(255,255,255,0.5), rgba(255,255,255,0));
        border-radius: 4px;
        box-shadow: 0 1px 2px rgba(37,46,58,0.06);
    }
    .app-hero-section .badge.bg-warning {
        font-size: 0.85rem;
        background: #f0b34b; // But .bg-warning already background yellow; overriding with fresh? Need maybe keep warning hue? Use accent #e8873a? Should be functional accent.
        color: #252e3a;
        border-radius: 4px;
        box-shadow: 0 2px 6px rgba(232,135,58,0.25);
        transition: background-color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease;
    }
    .contact-channels-section article,
    .contact-quick-section .contact-card {
        padding: var(--space-md) !important;
        background: #ffffff;
        border-radius: 6px;
        box-shadow: 0 1px 3px rgba(37,46,58,0.08), 0 4px 12px rgba(37,46,58,0.04);
        transition: box-shadow 0.2s ease-in-out, background-color 0.2s ease-in-out;
    }
}
Need "outline" maybe none. But if adding background to col-lg-7, might visually alter section but okay. Need "background: linear-gradient(...)" maybe fresh. But careful: original .app-hero-section .row .col-lg-7 maybe has existing background; overriding can change but visual. Good.

However constraints: "font-family, font-size, font-weight, line-height unchanged" We keep font-size. "padding, margin keep similar ±20%" We keep same. "border-width" not change and don't add border because border width would be change. We can add box-shadow, border-radius, colors. "transition timing, easing, duration" can change/add. Good.

Need maybe include "accent-color" or "caret-color"? no.

Need maybe use CSS variables? The original uses var(--space-md). If we redefine --space-md? Not in file. Could define :root? That would be extra selector? Not allowed maybe. No.

Need preserve selector list with article, .contact-card. yes.

Need maybe include "box-shadow: none" if target subtle shadows or none? It says tight-rhythm subtle shadows or none. We'll use subtle shadows.

Need maybe use color palette:
--sidebar-dark #252e3a
--main-light #f7f5f0 maybe
--accent #d97746? target "functional accent". Use accent #d97b4a or #c96f4a.
Need previous attempt didn't change enough; maybe use bold palette: sidebar-dark, main-light. Use #253341? Actually target says sidebar darker (#252e3a), main lighter. Use #252e3a. Accent maybe #d98e4a. But .bg-warning needs warning; if we set background #f2b84b maybe. Distinct enough? Since original bootstrap warning yellow probably #ffc107. Our #f2b84b similar. To be more distinct, use amber/orange #e8993a. But functional accent for actions maybe #d9734c. In badge, warning color should signal warning. #e8993a is more orange.

Need perhaps add background on entire col? Could be weird but okay.

Need no markdown fences, no explanations. Final output only CSS.

But wait: user says "Output the rewritten CSS now (no markdown, no preamble)". So final must only contain CSS. Good.

Need perhaps include exactly the media query and rules. Should we include declarations not in original? Yes. Need maybe preserve all selectors and layout "text-align" and "font-size". Good.

Let's craft robust CSS.

Need watch "outline styles" maybe no. "filter, backdrop-filter" maybe add if decorative. Could use filter? But not necessary.

Need "border-radius" adjustment. Since target small border radius 2-6px. Use 6px for cards, 4px for badge, 2px maybe for col? Use 4px.

Need "transition timing, easing, duration" For card: transition: box-shadow .2s ease, background-color .2s ease, transform .2s ease; Adding transform transition but transform property not used. It's okay if not triggered. But "transition" not layout. However adding transform to hover not possible because no hover. We can add transition anyway. But if we add transition without state, no effect. Should add not needed. Maybe add declaration `transition: box-shadow 0.25s ease-in-out, background-color 0.25s ease-in-out;` okay.

Need maybe add `box-shadow` to contact-cards; because tight-rhythm small shadows. Multi-layer? Use `0 1px 2px rgba(37,46,58,0.06), 0 4px 12px rgba(37,46,58,0.04)`.

Need maybe use `background-color` not background? Original .bg-warning background color already. We can use `background: #e8993a;` but Bootstrap `.bg-warning` has `background-color: #ffc107!important`? Likely yes. When class `badge bg-warning`, Bootstrap's `.bg-warning` uses `--bs-warning-rgb` and `background-color: rgba(var(--bs-warning-rgb), var(--bs-bg-opacity))!important;` Our custom style with same specificity? `.app-hero-section .badge.bg-warning` (0,3,0) vs `.bg-warning` (0,1,0) but important in Bootstrap perhaps. Bootstrap `.bg-warning` uses `!important`? In Bootstrap 5, .bg-warning { --bs-bg-opacity: 1; background-color: rgba(var(--bs-warning-rgb), var(--bs-bg-opacity)) !important; } Yes important. Our declaration without !important won't override. Need add `!important` or use `background-color` with `!important`. Since target visual changes need override. We can set `background: #e8993a !important;`. But background shorthand includes background-color. Better `background-color: #e8993a !important;` to override. But does modifying .badge.bg-warning background to orange weird? Fine. Similarly color maybe Bootstrap `.text-warning`? The badge likely has `color: #000`? Actually `badge` default color is maybe var(--bs-badge-color) #fff? With bg-warning, should use dark text for contrast. Override with `color: #252e3a !important;`. Could use `!important` to ensure override. This is visual, allowed.

What about `.app-hero-section .row .col-lg-7` maybe existing `background`? Add background with semi-transparent maybe without important. Should be okay. But maybe changing background to gradient could violate "background"? allowed. Use `background-color: #f8f6f3;`? Since mobile hero section maybe text block, background might bleed. But no issue.

Could we add `border-radius: 4px` to `col-lg-7`? It could clip? If no overflow, okay. Need maybe use `box-sizing`? no.

Need maybe add `box-shadow` to badge? small.

Need maybe add `text-shadow`? Could to hero text? Not necessary. But user asked refresh all visual properties. We can add `text-shadow: 0 1px 2px rgba(255,255,255,0.5)`? That's subtle but maybe unnecessary. Since hero title maybe has h1? This selector targets column, not text. Text shadow would be inherited? `text-shadow` inherited, yes. Could apply to all text in column. Maybe not desired but okay. But adding text-shadow can improve. Use `text-shadow: 0 1px 2px rgba(255,255,255,0.6);` But if background is light, okay. Maybe avoid.

Need "accent-color" maybe no.

Need perhaps change `caret-color` no.

Need maybe change `outline` no.

Let's produce final:
@media (max-width: 575.98px) {
    .app-hero-section .row .col-lg-7 {
        text-align: center;
        color: #252e3a;
        background: linear-gradient(180deg, #ffffff 0%, #f2ede4 100%);
        border-radius: 4px;
        box-shadow: 0 1px 2px rgba(37, 46, 58, 0.06);
    }

    .app-hero-section .badge.bg-warning {
        font-size: 0.85rem;
        background-color: #e8993a !important;
        color: #252e3a !important;
        border-radius: 4px;
        box-shadow: 0 1px 3px rgba(232, 153, 58, 0.35);
        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: #ffffff;
        border-radius: 6px;
        box-shadow: 0 1px 2px rgba(37, 46, 58, 0.08), 0 4px 12px rgba(37, 46, 58, 0.04);
        transition: box-shadow 0.2s ease-in-out, background-color 0.2s ease-in-out;
    }
}
Need check all constraints. Does "width height padding margin" changed? Padding unchanged. Background-color no layout. Border-radius no layout. Box-shadow no layout. Transition no layout. Color no layout. Good. Selectors preserved.

Potential issue: `.contact-channels-section article, .contact-quick-section .contact-card { padding: var(--space-md) !important; ... }` Original rule inside media query included `padding: var(--space-md) !important;` We kept. Good.

Need maybe "No markdown fences" yes final not include fences. But ensure no "Here's". Good.

However let's think if `background: linear-gradient(...)` on `.app-hero-section .row .col-lg-7` might be too much and have same specificity but no need important. Could change if existing background already. Good.

Need perhaps keep "font-size:0.85rem" not changed. yes.

Could maybe use `filter` to add `drop-shadow`? not needed.

Could maybe use `outline: none`? no.

Need perhaps include "button/input focus"? no.

Let's see if there are no other selectors in file? The file #块2/2 only this. Good.

Potential issue with `@media (max-width: 575.98px)` and `text-align: center;` order? We keep first declaration. Good.

Need maybe include `padding: var(--space-md) !important` after other properties? order doesn't matter. But if we inject color before, okay.

Need maybe "transition timing, easing, duration" allowed. We changed/add. Good.

Need maybe "filter, backdrop-filter" none. Fine.

Need maybe "opacity" none. Fine.

Need maybe "gradient colors and stops" changed? We added gradient. Good.

Need maybe "border-color and border-style (not width)" none. Fine.

Need maybe "CSS custom properties values" none. Fine.

Let's consider if `color: #252e3a` on hero col might override inherited color and affect readability on a hero section with dark background. We're changing visual identity; okay. But if hero background is dark, dark text could be unreadable. However original CSS does not include color, so we shouldn't assume. The target style says sidebar darker, main lighter. On mobile, maybe best to not set text color on entire col? But we want distinct. Could use `color: #252e3a` but if background is dark, no. Need maybe use currentColor? no.

Maybe safer: add background with light gradient and color dark. Since we set background, readable. But background on column might conflict with existing hero section background; still okay.

Could maybe set `background: rgba(255,255,255,0.7)` with `backdrop-filter: blur(6px);` It's visual but if backdrop-filter unsupported no issue. But target "tight-rhythm" not glassy. Use gradient.

Need maybe "border-radius" on col with gradient will be visible? If background covers entire col, yes. But if column has no padding, the rounded corners could create gaps from parent background. Could be undesirable. Better avoid background on col to not alter layout. But color change is expected. Could just not add background to col, only color? But "background" all colors values need change? The task says "All color values: background, color, border-color, fill, stroke, outline-color" means change any present. There are no present. Need add enough. But maybe don't add background to col; still visual through color? Could add `color` and `text-shadow`. But distinct less. Hmm.

Maybe target palette: "Sidebar darker (#252e3a), main lighter" We can set `.contact-channels-section article` / `.contact-card` `background-color: #fff;` and `.col-lg-7` `color: #252e3a`. Good. Don't set background on col. But then no background change? There is background-color on cards. Enough. Could add `background: transparent`? not good. Perhaps add `border-radius` and `box-shadow` to col? If no background, box-shadow may not show. `border-radius` on col without background doesn't show. Could set `box-shadow: inset 0 0 0 1px rgba(37,46,58,0.04);` That is an inset ring with no layout, colored via box-shadow. It will show even without background? It draws inside padding box; if no background, box-shadow can render on transparent background; yes it draws outside/inside border-box but if no border and no background, inset shadow will show? Inset shadow is drawn inside padding box, but if element has no background, still visual? It draws over background of element; if element background transparent, the shadow may still be visible? I think box-shadow draws shadow of the element's border-box; inset shadow is drawn inside the border box. It will be visible (a rectangle) regardless of element background? It is drawn over the element's