refactor: clarify visual motif grammar

apps/web/src/styles/global.css

@@ -41,3 +41,6 @@ footer{min-height:118px;background:var(--deep);color:#dbe4df;padding:28px max(32
 @media(max-width:720px){.signal-heading{display:block;padding-top:45px}.signal-count{display:inline-block;margin-top:14px}.signal-grid{grid-template-columns:1fr}.signal-card__top{align-items:flex-start}.source-strip{margin-bottom:4px}}
 .load-more,.signal-more{display:inline-flex;align-items:center;gap:8px;padding:12px 20px;border:1px solid #c8d3cb;border-radius:10px;background:#f8faf5;color:#526662;font-size:14px;text-decoration:none;transition:.2s ease}.load-more:hover,.signal-more:hover{background:#eef2ec;border-color:#a8b8af}.load-more span,.signal-more span{color:#405552;font-size:13px}
 .not-found{min-height:calc(100vh - 204px);display:flex;flex-direction:column;align-items:flex-start;justify-content:center;padding-block:70px}.not-found__float{width:130px;height:130px;display:grid;place-items:center;position:relative;margin-bottom:28px;border:1px solid #b8c8be;border-radius:50%;color:#55751e;box-shadow:0 0 0 16px #dce7d722}.not-found__float strong{position:absolute;right:-18px;bottom:5px;padding:5px 9px;border-radius:20px;background:var(--deep);color:var(--lime);font:italic 14px Georgia,serif}.not-found h1{margin:14px 0 22px;font:400 clamp(58px,8vw,105px)/.88 Georgia,serif;letter-spacing:-.06em}.not-found h1 em{color:#497074;font-weight:400}.not-found p{max-width:600px;color:#4d605d;font-size:17px;line-height:1.6}.not-found>a{display:flex;align-items:center;gap:10px;margin-top:18px;padding:14px 18px;border-radius:10px;background:var(--deep);color:#fff;font-weight:750;text-decoration:none}.not-found>a .fish-icon{color:var(--lime)}
+
+/* Brand grammar: radar belongs to coordinates; incomplete signals use a field-note edge, not decorative ripples. */
+.detail-card:before,.signal-card:after{content:none}.signal-card{border-top:3px solid #c9ad55}