We need rewrite CSS visually in conservative mode. Need change colors, shadows, radius, transitions, gradients, etc. Must preserve selectors and layout values except visual properties. Need target style dense-dashboard, tight-rhythm. Need ensure column counts etc differ from other files? We are given original CSS. Need output only CSS.

We must honor constraints. Let's inspect original. Need change color palette from coral to cool grays/slate with accent blue #3b82f6, white cards on slate background. Values: --color-primary: #3b82f6; --color-primary-dark: #1d4ed8 maybe; --color-accent: #93c5fd? --color-surface: #f8fafc or #ffffff? White cards on slate bg: body background maybe #f1f5f9 or #0f172a? Since "Cool grays #1e293b, #334155, accent blue #3b82f6, white cards on slate background". Need adapt variables. Original uses --color-surface as background for cta-inner, but also body? Actually body color only; background not set in original. We can set body background? Original has no body background. We can add? We need not change layout, but background is visual. Could set body { background-color: ... }? Selector exists "body { color ... line-height ... }" so can add background-color. That's okay.

Need preserve all selectors and properties? We can change values. Need preserve padding/margin within ±20%. Could adjust --space-section/card/gap maybe? The target styles compact spacing. Original --space-section: 3rem, --space-card: 1.25rem, --space-gap: 1rem. Need "compact spacing (Aggressive: padding 8-16px, gap 8-12px)". But we cannot change padding/margin values except within ±20% per rules: "--space-card" is custom property used for padding. If we change it from 1.25rem to 1rem, that's -20%. Actually 1.25rem to 1rem is 20% decrease, allowed. --space-gap from 1rem to 0.75rem is -25%, not allowed. But could make 0.875rem? That's -12.5%. --space-section 3rem to 2.5rem is -16.7%, allowed. The compact target says aggressive padding 8-16px, gap 8-12px. In rem these could be 0.5-1rem, 0.5-0.75rem. But margin/padding changes restricted to ±20% of original. Need balance: maybe keep --space-card: 1rem (from 1.25 = -20%), --space-gap: 0.875rem (from 1 = -12.5%), --space-section: 2.5rem (from 3 = -16.7%). That maintains within ±20% overall. Also in media query 640px original --space-section: 2rem, --space-card:1rem, --space-gap:0.75rem. We can change to values? Since already compact. Need keep similar. Maybe change to 1.75rem? 1rem? 0.625rem? But must not majorly change.

Need change radius values: original --radius-sm:4px, md:8px, lg:12px, xl:16px. Target small border-radius 2-6px. Need change to perhaps --radius-sm:2px; --radius-md:4px; --radius-lg:6px; --radius-xl:8px. That's okay. But must maintain --radius used in selectors; can set values.

Need change shadows: redesign. Original subtle shadows. Dense dashboard with subtle or none. Use cool gray blue shadows. Maybe --shadow-sm: 0 1px 2px rgba(15,23,42,0.06); --shadow-md: 0 1px 2px rgba(15,23,42,0.05), 0 1px 3px rgba(15,23,42,0.1); --shadow-lg: 0 2px 4px rgba(15,23,42,0.06), 0 4px 8px rgba(15,23,42,0.08). Need differ from original offsets. Could use multi-layer.

Need change transition: original 0.1s ease. Target maybe 0.15s ease-in-out? Could use cubic-bezier. Need preserve? Transition timing can change. Use --transition: 0.12s cubic-bezier(0.4,0,0.2,1). Good.

Need change heading-weight? Original --heading-weight:600; not typography? It is a custom property controlling font-weight, cannot change? It's visual? But "font-weight unchanged" means we must not change font-weight values. This custom property value should remain 600. Body line-height 1.7? Line-height is typography fixed, leave same. We should not alter.

Need change colors of :root and all references. Add --color-bg perhaps? Original doesn't have. We can set body background-color: #f1f5f9 or #e2e8f0? On slate background, white cards. Let's use #f1f5f9 for bg. Update --color-text to #0f172a. --color-surface maybe #ffffff? But original .cta-inner background: var(--color-surface) so surface should be white card. Good. --color-primary: #3b82f6, dark #1e40af, accent #93c5fd maybe. Need rgb variables: --rgb-primary: 59,130,246; --rgb-accent: 147,197,253. Are rgb variables used? Not in original? Not used except defined. We update anyway.

Need update conditional decoration: .card:hover transform translateY(-4px) to maybe translateY(-2px) for tight rhythm. Original transform is layout? It's visual, can change? "position, display etc unchanged" but transform? It's not listed as forbidden. Could change to -2px. But "card hover" decoration. Need keep? We can change transform value? It's visual, but transform is not in the forbidden list? It says only colors, shadows, radius, decorative properties may change. But the target says layout structure unchanged. transform can affect layout? It doesn't affect document flow, but visual. The original uses transform: translateY(-4px) on hover. We can change to translateY(-2px) to fit dense dashboard. However constraints include "width, height, padding, margin" and not transform, so allowed.

Need update .card border-left: 3px solid var(--color-primary). Could change to 3px solid var(--color-primary) but color changes. Should we keep width? It says border-color/styles can change but not border-width. So keep 3px.

Need update header shadow to maybe 0 1px 2px rgba(15,23,42,0.06), 0 1px 3px rgba(15,23,42,0.08). Fine.

Need ensure selectors unchanged. There is weird whitespace/indentation with spaces. Output should preserve selectors but formatting can be cleaned? We need same selectors. We can keep same structure.

Need maybe change --space-section etc carefully within ±20%. Let's compute original values:
--space-section: 3rem. target 2.5rem = -16.7 OK.
--space-card: 1.25rem. target 1rem = -20%, OK.
--space-gap: 1rem. target 0.875rem = -12.5%, OK.
Media query at max-width:640px original --space-section:2rem; --space-card:1rem; --space-gap:0.75rem. If we alter to --space-section:1.75rem (-12.5%), --space-card:0.875rem (-12.5%), --space-gap:0.625rem (-16.7%). Does this conflict with compact? yes. But we can keep? Need change values anyway? It says --space-* values are visual? Actually they are spacing values, but custom properties can be changed? Wait "CSS custom properties (--color-*, --shadow-*) values" specifically only color and shadow custom properties. But previous "padding, margin (keep similar values)" likely applies to actual values, not custom properties? However --space-* are used as padding/gap values, so changing them changes layout. But constraints say can change within ±20%. So okay. Need not necessarily change every custom property? We can change visual only colors etc. But if we don't change --space values, layout more balanced, not target. Yet target dense-dashboard wants compact. To fit tight rhythm, we should make spacing compact within allowed margins. Good.

Need maybe adjust .hero padding: original "padding: 2rem 0;" and .cta-inner "padding: 3rem;" etc. The constraint says padding/margin keep similar ±20%. We can change .hero padding to 1.5rem 0? 2rem to 1.5 = -25%, not allowed. Can't. Could change to 1.75rem 0 = -12.5%. But "compact" target maybe want 1.5, but restriction allows max -20%? Actually 2rem * 0.8 = 1.6rem, so 1.5 not allowed. Could use 1.625rem? Not typical but allowed. Maybe keep 2rem? It is fine. cta-inner padding 3rem to 2.5rem = -16.7 allowed. .partner-grid gap: 2rem to 1.5rem = -25% not allowed? gap is spacing property, not listed? It says "gap, row-gap, column-gap (keep similar)" likely ±20%? In intro says keep similar, not explicit for gap. They say "gap, row-gap, column-gap (keep similar)". So keep within ±20% or maybe same. Changing 2rem to 1.75rem = -12.5 ok. .stats-grid gap: 3rem to 2.5rem = -16.7 ok.

Need be careful with media queries: original @media queries have grid-template-columns reductions but also include grid-template-columns on .partner-grid? Wait .partner-grid is flex originally, but in media query they set grid-template-columns? That's weird because it's display flex in base. Actually media query at 1024: .partner-grid { grid-template-columns: repeat(3, 1fr) !important; } but display remains flex. This is bug. We must preserve selectors and values exactly? We cannot change layout values, so keep exactly. But perhaps it's okay.

Need maybe update @keyframes partnerScroll: 0% { transform: translateX(0); } 100% { transform: translateX(-50%); } can't change transform? It's animation value, can change? The keyframes values inside CAN change per instructions. But layout? We can keep same. No need.

Need update accent colors and hover. Need use --color-accent maybe #60a5fa. Since text/hover uses accent. Let's choose palette:
--color-primary: #3b82f6 (blue-500)
--color-primary-dark: #1e40af (blue-800)
--color-accent: #60a5fa (blue-400)
--color-surface: #ffffff (white)
--color-text: #0f172a (slate-900)
--color-muted? not needed.
--rgb-primary: 59,130,246
--rgb-accent: 96,165,250

Need adjust body background. Since original body has color, line-height. Add background-color: #f1f5f9; maybe. But be careful: body line-height unchanged. Add background color no layout.

Need maybe set .card background: #fff? Not in original. Cards likely inherit body background. To make white cards on slate background, we need add background-color to .card. But selector `.card, [class*="card"]` exists. We can add background-color: var(--color-surface). Also maybe border? It has border-left. Need maybe add border: 1px solid rgba(...)? We can use border-color? But there is existing border-left. Adding border-top etc would alter visual but not layout? It can affect box-size? Since box-sizing? Not specified, adding border could change layout unless box-sizing: border-box globally? Not defined. But no need. Use box-shadow for card look. Could add background-color only. Does changing background color violate? No.

Need maybe change --color-surface in cta-inner background to white. Good.

Need maybe update .btn border-radius etc.

Need ensure no non-CSS output. Need preserve all selectors exactly? We need be careful with whitespace and comments? Comments are allowed? The original has comments. We can remove? It's not selector. But output should be only CSS. We can keep or remove comments? The instructions say output rewritten CSS, no AI comments. We can include structural comments? Better to omit or keep? "No  comments" but can keep original comments? Since output "ONLY rewritten CSS" probably comments okay but no need. We should produce clean CSS, but preserving selectors. Comments don't matter. We can include section comments maybe.

Need also check "File fingerprint: ..." irrelevant.

Need think about "Other files already used: card-mosaic+airy-rhythm. This file's specific values (column counts, gaps, hex codes, shadow specs) MUST differ." We don't know other files. Just ensure our values are different from original and maybe unique. Fine.

Need produce CSS exactly with all selectors. Let's map original selectors:

:root { ... }

body { color: var(--color-text); line-height: var(--body-line-height); }
h1, h2, h3, h4 { font-weight: var(--heading-weight); }
section, .section { padding-top: var(--space-section); padding-bottom: var(--space-section); }
.card, [class*="card"] { border-radius: var(--radius-lg); box-shadow: var(--shadow-md); padding: var(--space-card); transition: var(--transition); }
.btn, button[class*="btn"], a[class*="btn"] { border-radius: var(--radius-md); transition: var(--transition); }
a:not([class]) { color: var(--color-primary); transition: var(--transition); }

.news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-gap); }
.feature-list { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-gap); }
.hero { padding: 2rem 0; } .hero-content { max-width: 560px; }
.testimonial-list { column-count: 2; column-gap: var(--space-gap); }
.testimonial-list > * { break-inside: avoid; margin-bottom: var(--space-gap); }
.partner-grid { display: flex; gap: 2rem; overflow: hidden; animation: partnerScroll 20s linear infinite; }
@keyframes partnerScroll { 0% { transform: translateX(0); } 100% { transform: translateX(-50%); } }
.faq-list { max-width: 800px; margin: 0 auto; }
.stats-grid { display: flex; justify-content: center; gap: 3rem; }
.cta-inner { background: var(--color-surface); border-radius: var(--radius-xl); padding: 3rem; text-align: center; }
.page-main { max-width: 860px; margin: 0 auto; }

.card:hover, [class*="card"]:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
a:not([class]):hover { color: var(--color-accent); }
.card { border-left: 3px solid var(--color-primary); }
header, .header, .navbar { box-shadow: 0 2px 8px rgba(0,0,0,.06); }

@media (max-width: 1024px) {
    .news-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .feature-list { grid-template-columns: repeat(2, 1fr) !important; }
    .partner-grid { grid-template-columns: repeat(3, 1fr) !important; }
    .stats-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .hero-inner { grid-template-columns: 1fr !important; }
}
@media (max-width: 640px) {
    :root { --space-section: 2rem; --space-card: 1rem; --space-gap: 0.75rem; }
    .news-grid { grid-template-columns: 1fr !important; }
    .feature-list { grid-template-columns: 1fr !important; }
    .faq-list { grid-template-columns: 1fr !important; }
    .testimonial-list { column-count: 1 !important; }
    .partner-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .stats-grid { grid-template-columns: repeat(2, 1fr) !important; }
    .cta-inner { grid-template-columns: 1fr !important; }
}

Need preserve these selectors. We can add background-color to body, card. Add to existing property declarations. Adding properties is okay? "only colors, shadows, and decorative properties may change" includes adding background? Yes. But not adding layout properties like display? Background-color is color. border-left width unchanged.

Need perhaps change .card border-left to border-left: 3px solid var(--color-primary); same. Could change to border-left: 3px solid var(--color-primary-dark)? Maybe primary. No need.

Need perhaps add `background: var(--color-surface);` to .card. If we add, it's visual. Need ensure `[class*="card"]` might select e.g. .feature-list? No, class*="card" only contains "card". .partner-grid doesn't. .cta-inner? no. So fine.

Need perhaps