Apply Design A: dark theme, type badges, code cleanup

Visual:
- Dark theme throughout (#111 bg, #1c1c1c panels, #2a2a2a borders)
- Type badges with color: Monster=orange, Spell=green, Trap=purple
- Owned count shown as ×3 (highlighted) or — (dimmed)
- Printing column headers in CardRow
- Card detail panel: type badge, attribute, race, level stars

Cleanup:
- Replace index.css (was Vite boilerplate) with dark base + shared CSS classes
  (.card-row-header:hover, .filter-chip, .icon-btn, modal styles)
- Clear App.css (Vite boilerplate, unused)
- Remove Footer.css (modal styles consolidated into index.css)
- Extract useDebounce to src/hooks/useDebounce.js
- Remove react-window (installed but never used)
- App.jsx: remove unnecessary wrapper div
- gitignore: add mockups/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/index.css

@@ -1,110 +1,94 @@
-:root {
-  --text: #6b6375;
-  --text-h: #08060d;
-  --bg: #fff;
-  --border: #e5e4e7;
-  --code-bg: #f4f3ec;
-  --accent: #aa3bff;
-  --accent-bg: rgba(170, 59, 255, 0.1);
-  --accent-border: rgba(170, 59, 255, 0.5);
-  --social-bg: rgba(244, 243, 236, 0.5);
-  --shadow:
-    rgba(0, 0, 0, 0.1) 0 10px 15px -3px, rgba(0, 0, 0, 0.05) 0 4px 6px -2px;
+*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
 
-  --sans: system-ui, 'Segoe UI', Roboto, sans-serif;
-  --heading: system-ui, 'Segoe UI', Roboto, sans-serif;
-  --mono: ui-monospace, Consolas, monospace;
-
-  font: 18px/145% var(--sans);
-  letter-spacing: 0.18px;
-  color-scheme: light dark;
-  color: var(--text);
-  background: var(--bg);
-  font-synthesis: none;
-  text-rendering: optimizeLegibility;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-
-  @media (max-width: 1024px) {
-    font-size: 16px;
-  }
-}
-
-@media (prefers-color-scheme: dark) {
-  :root {
-    --text: #9ca3af;
-    --text-h: #f3f4f6;
-    --bg: #16171d;
-    --border: #2e303a;
-    --code-bg: #1f2028;
-    --accent: #c084fc;
-    --accent-bg: rgba(192, 132, 252, 0.15);
-    --accent-border: rgba(192, 132, 252, 0.5);
-    --social-bg: rgba(47, 48, 58, 0.5);
-    --shadow:
-      rgba(0, 0, 0, 0.4) 0 10px 15px -3px, rgba(0, 0, 0, 0.25) 0 4px 6px -2px;
-  }
-
-  #social .button-icon {
-    filter: invert(1) brightness(2);
-  }
-}
+html, body, #root { height: 100%; }
 
 body {
-  margin: 0;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
+  background: #111;
+  color: #e0e0e0;
+  font-size: 14px;
+  -webkit-font-smoothing: antialiased;
 }
 
-#root {
-  width: 100%;
-  margin: 0;
-  text-align: left; /* optional: better for layout apps */
-  min-height: 100svh;
-  display: flex;
-  flex-direction: column;
-  box-sizing: border-box;
-}
+/* Card row — :hover can't be done with inline styles */
+.card-row-header:hover { background: #1a1a1a !important; }
 
+/* Filter chips */
+.filter-chip {
+  padding: 3px 12px;
+  border-radius: 20px;
+  border: 1px solid #333;
+  background: transparent;
+  color: #666;
+  font-size: 12px;
+  cursor: pointer;
+  transition: border-color 0.15s, color 0.15s;
+}
+.filter-chip:hover { border-color: #555; color: #bbb; }
+.filter-chip.active     { background: #e0e0e0; color: #111; border-color: #e0e0e0; }
+.filter-chip.active-m   { background: #c07020; color: #fff; border-color: #c07020; }
+.filter-chip.active-s   { background: #1a7a5e; color: #fff; border-color: #1a7a5e; }
+.filter-chip.active-t   { background: #7a2060; color: #fff; border-color: #7a2060; }
 
-h1,
-h2 {
-  font-family: var(--heading);
-  font-weight: 500;
-  color: var(--text-h);
-}
-
-h1 {
-  font-size: 56px;
-  letter-spacing: -1.68px;
-  margin: 32px 0;
-  @media (max-width: 1024px) {
-    font-size: 36px;
-    margin: 20px 0;
-  }
-}
-h2 {
-  font-size: 24px;
-  line-height: 118%;
-  letter-spacing: -0.24px;
-  margin: 0 0 8px;
-  @media (max-width: 1024px) {
-    font-size: 20px;
-  }
-}
-p {
-  margin: 0;
-}
-
-code,
-.counter {
-  font-family: var(--mono);
-  display: inline-flex;
+/* Amount +/− buttons */
+.icon-btn {
+  width: 22px;
+  height: 22px;
   border-radius: 4px;
-  color: var(--text-h);
+  border: 1px solid #333;
+  background: #222;
+  color: #aaa;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 14px;
+  line-height: 1;
 }
+.icon-btn:hover:not(:disabled) { background: #2e2e2e; border-color: #444; }
+.icon-btn:disabled { opacity: 0.4; cursor: default; }
 
-code {
-  font-size: 15px;
-  line-height: 135%;
-  padding: 4px 8px;
-  background: var(--code-bg);
+/* Import modal */
+.modal-backdrop {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.6);
+  backdrop-filter: blur(2px);
+  z-index: 1000;
+  animation: fadeIn 0.15s ease;
 }
+@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
+
+.import-modal {
+  position: fixed;
+  top: 50%;
+  left: 50%;
+  transform: translate(-50%, -50%);
+  background: #1e1e1e;
+  color: #e0e0e0;
+  padding: 2rem 2.5rem;
+  border-radius: 12px;
+  border: 1px solid #333;
+  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.7);
+  z-index: 1001;
+  max-width: 90%;
+  min-width: 300px;
+  text-align: center;
+  animation: popIn 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
+}
+@keyframes popIn {
+  from { opacity: 0; transform: translate(-50%, -48%) scale(0.92); }
+  to   { opacity: 1; transform: translate(-50%, -50%) scale(1); }
+}
+.import-modal button {
+  margin-top: 1.25rem;
+  padding: 0.4rem 1.4rem;
+  cursor: pointer;
+  background: #2a2a2a;
+  color: #e0e0e0;
+  border: 1px solid #444;
+  border-radius: 6px;
+  font-size: 0.9rem;
+  transition: background 0.15s;
+}
+.import-modal button:hover { background: #333; }