Hardening responsiveness and SEO

hdyc-svelte/src/app.css

@@ -246,6 +246,28 @@ a {
 a:hover {
   color: var(--accent-dark);
 }
+a:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+  border-radius: 6px;
+}
+
+.skip-link {
+  position: fixed;
+  top: 0.6rem;
+  left: 0.6rem;
+  z-index: 500;
+  background: var(--bg-elevated);
+  color: var(--text);
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  padding: 0.5rem 0.8rem;
+  transform: translateY(-160%);
+  transition: transform 0.2s ease;
+}
+.skip-link:focus-visible {
+  transform: translateY(0);
+}
 
 /* ─── Layout Shell ───────────────────────────────────────── */
 
@@ -264,6 +286,12 @@ a:hover {
   border-bottom: 1px solid var(--border);
 }
 
+.header-left {
+  display: flex;
+  align-items: center;
+  gap: 0.75rem;
+}
+
 .site-logo {
   display: flex;
   align-items: center;
@@ -281,15 +309,51 @@ a:hover {
 .header-right {
   display: flex;
   align-items: center;
-  gap: 1rem;
+  gap: 0.65rem;
+}
+
+.desktop-header-search {
+  width: min(420px, 42vw);
+}
+
+.header-icon-btn {
+  display: none;
+  align-items: center;
+  justify-content: center;
+  width: 44px;
+  height: 44px;
+  border: 1px solid var(--border);
+  border-radius: 50%;
+  background: var(--input-bg);
+  color: var(--text);
+  cursor: pointer;
+  font-size: 1rem;
+  line-height: 1;
+  transition: border-color 0.2s, box-shadow 0.2s, background 0.2s;
+}
+.header-icon-btn:hover {
+  border-color: var(--accent);
+}
+.header-icon-btn:focus-visible {
+  outline: none;
+  box-shadow: 0 0 0 3px var(--accent-glow);
+}
+
+.mobile-header-search {
+  padding: 0.75rem 1rem;
+  border-bottom: 1px solid var(--border);
+  background: var(--header-bg);
+}
+.mobile-header-search[hidden] {
+  display: none !important;
 }
 
 .theme-toggle {
   display: inline-flex;
   align-items: center;
   justify-content: center;
-  width: 36px;
-  height: 36px;
+  width: 44px;
+  height: 44px;
   border-radius: 50%;
   border: 1px solid var(--border);
   background: var(--input-bg);
@@ -395,12 +459,25 @@ a:hover {
 
 .hamburger {
   display: none;
-  background: none;
-  border: none;
+  align-items: center;
+  justify-content: center;
+  width: 44px;
+  height: 44px;
+  background: var(--input-bg);
+  border: 1px solid var(--border);
+  border-radius: 50%;
   color: var(--text);
-  font-size: 1.4rem;
+  font-size: 1.2rem;
   cursor: pointer;
-  padding: 0.25rem;
+  padding: 0;
+  transition: border-color 0.2s, box-shadow 0.2s, background 0.2s;
+}
+.hamburger:hover {
+  border-color: var(--accent);
+}
+.hamburger:focus-visible {
+  outline: none;
+  box-shadow: 0 0 0 3px var(--accent-glow);
 }
 
 .site-body {
@@ -419,6 +496,9 @@ a:hover {
   padding: clamp(1.5rem, 2vw, 3rem);
   width: 100%;
 }
+.main-content:focus {
+  outline: none;
+}
 
 .site-footer {
   padding: 2rem;
@@ -431,22 +511,35 @@ a:hover {
 /* ─── Page Utilities ─────────────────────────────────────── */
 
 .breadcrumbs {
-  display: flex;
-  align-items: center;
-  gap: 0.4rem;
   font-size: 0.82rem;
   color: var(--text-muted);
   margin-bottom: 1.5rem;
 }
+.breadcrumbs ol {
+  list-style: none;
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.4rem;
+  margin: 0;
+  padding: 0;
+}
+.breadcrumbs li {
+  display: inline-flex;
+  align-items: center;
+  color: var(--text-muted);
+}
+.breadcrumbs li + li::before {
+  content: '›';
+  opacity: 0.4;
+  margin-right: 0.4rem;
+}
 .breadcrumbs a {
   color: var(--text-muted);
 }
 .breadcrumbs a:hover {
   color: var(--accent);
 }
-.breadcrumbs .sep {
-  opacity: 0.4;
-}
 
 .page-title {
   font-size: 1.8rem;
@@ -459,6 +552,10 @@ a:hover {
   background-clip: text;
 }
 
+.calculator-page-title {
+  margin-bottom: 1.25rem;
+}
+
 .page-subtitle {
   color: var(--text-muted);
   font-size: 1rem;
@@ -531,6 +628,11 @@ a:hover {
   box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
   color: var(--accent);
 }
+.calc-list-item:focus-visible {
+  outline: none;
+  border-color: var(--accent);
+  box-shadow: 0 0 0 3px var(--accent-glow);
+}
 
 /* ─── Related Converters ─────────────────────────────────── */
 
@@ -554,6 +656,11 @@ a:hover {
   color: var(--accent);
   border-color: var(--accent);
 }
+.related-chip:focus-visible {
+  outline: none;
+  border-color: var(--accent);
+  box-shadow: 0 0 0 3px var(--accent-glow);
+}
 
 /* ─── SEO Content ────────────────────────────────────────── */
 
@@ -633,7 +740,7 @@ a:hover {
 
 @media (max-width: 1024px) {
   .hamburger {
-    display: block;
+    display: inline-flex;
   }
   .site-body {
     gap: 1rem;
@@ -642,9 +749,31 @@ a:hover {
 }
 
 @media (max-width: 768px) {
+  .site-header {
+    padding: 0 1rem;
+  }
+  .site-logo {
+    font-size: 1rem;
+    gap: 0.4rem;
+  }
+  .desktop-header-search {
+    display: none;
+  }
+  .header-icon-btn {
+    display: inline-flex;
+  }
+  .mobile-header-search {
+    padding: 0.65rem 1rem;
+  }
   .main-content {
     padding: 1.25rem;
   }
+  .breadcrumbs {
+    margin-bottom: 1rem;
+  }
+  .page-title {
+    font-size: 1.5rem;
+  }
   .hero h1 {
     font-size: 1.8rem;
   }
@@ -665,6 +794,9 @@ a:hover {
   .stats-row {
     gap: 1.5rem;
   }
+  .seo-content {
+    padding: 1.25rem;
+  }
   .site-body {
     gap: 1rem;
     padding-inline: 1rem;