diff --git a/app.css b/app.css
new file mode 100644
index 0000000..41f53b2
--- /dev/null
+++ b/app.css
@@ -0,0 +1,150 @@
+:root {
+    color-scheme: light dark;
+    --bg: #f4f1e8;
+    --panel: #ffffff;
+    --ink: #202020;
+    --muted: #6b6b6b;
+    --accent: #cc0000;
+    --accent-dim: #e8d7d7;
+    --border: #202020;
+  }
+  @media (prefers-color-scheme: dark) {
+    :root {
+      --bg: #16171a;
+      --panel: #232529;
+      --ink: #eceff1;
+      --muted: #9aa0a6;
+      --accent: #ff5c5c;
+      --accent-dim: #3a2626;
+      --border: #4a4d52;
+    }
+  }
+  * { box-sizing: border-box; }
+  body {
+    margin: 0;
+    padding: 2rem 1rem 4rem;
+    background: var(--bg);
+    color: var(--ink);
+    font-family: "Courier New", Courier, monospace;
+    display: flex;
+    justify-content: center;
+  }
+  main { width: 100%; max-width: 720px; }
+  h1 {
+    font-size: 1.4rem;
+    margin: 0 0 0.25rem;
+    letter-spacing: 0.02em;
+  }
+  .subtitle {
+    color: var(--muted);
+    margin: 0 0 1.5rem;
+    font-size: 0.9rem;
+  }
+  .panel {
+    background: var(--panel);
+    border: 2px solid var(--border);
+    border-radius: 6px;
+    padding: 1.25rem 1.5rem;
+    margin-bottom: 1.5rem;
+  }
+  .name-row {
+    display: flex;
+    gap: 0.6rem;
+    flex-wrap: wrap;
+    margin-bottom: 0.5rem;
+  }
+  .slot {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    gap: 0.35rem;
+  }
+  .slot .index {
+    font-size: 0.7rem;
+    color: var(--muted);
+  }
+  .slot .role {
+    font-size: 0.65rem;
+    color: var(--accent);
+    font-weight: bold;
+    min-height: 1em;
+  }
+  .slot input {
+    width: 2.4rem;
+    height: 2.6rem;
+    text-align: center;
+    font-size: 1.3rem;
+    font-family: inherit;
+    background: var(--bg);
+    color: var(--ink);
+    border: 2px solid var(--border);
+    border-radius: 4px;
+  }
+  .slot input:focus {
+    outline: none;
+    border-color: var(--accent);
+  }
+  .symbols {
+    display: flex;
+    gap: 0.2rem;
+    flex-wrap: wrap;
+    justify-content: center;
+    max-width: 2.4rem;
+  }
+  .symbols button {
+    font-family: inherit;
+    font-size: 0.7rem;
+    padding: 0.1rem 0.3rem;
+    cursor: pointer;
+    background: var(--accent-dim);
+    color: var(--ink);
+    border: 1px solid var(--border);
+    border-radius: 3px;
+  }
+  .symbols button:hover { background: var(--accent); color: #fff; }
+  .hint {
+    font-size: 0.75rem;
+    color: var(--muted);
+    margin-top: 0.75rem;
+  }
+  .results {
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
+    gap: 0.75rem;
+    margin-top: 1rem;
+  }
+  .encounter {
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    padding: 0.75rem 0.9rem;
+    background: var(--bg);
+  }
+  .encounter .from {
+    font-size: 0.7rem;
+    color: var(--muted);
+    margin-bottom: 0.35rem;
+  }
+  .encounter .species {
+    font-size: 1.1rem;
+    font-weight: bold;
+  }
+  .encounter .level {
+    color: var(--accent);
+    font-size: 0.95rem;
+  }
+  h2 {
+    font-size: 1rem;
+    margin: 0 0 0.5rem;
+  }
+  p { line-height: 1.5; font-size: 0.9rem; }
+  code {
+    background: var(--accent-dim);
+    padding: 0.1rem 0.3rem;
+    border-radius: 3px;
+  }
+  footer {
+    color: var(--muted);
+    font-size: 0.75rem;
+    text-align: center;
+    margin-top: 2rem;
+  }
\ No newline at end of file