diff --git a/internal/webapp/static/app.js b/internal/webapp/static/app.js
index c7090bb..589e545 100644
--- a/internal/webapp/static/app.js
+++ b/internal/webapp/static/app.js
@@ -27,10 +27,51 @@ const els = {
   title: document.querySelector("#session-title"),
 };
 
+const readinessClassMap = {
+  unknown: "pill-neutral",
+  fragile: "pill-weak",
+  improving: "pill-warn",
+  interview_ready: "pill-good",
+  strong_signal: "pill-strong",
+};
+
+const reviewClassMap = {
+  candidate: "pill-neutral",
+  reviewed: "pill-good",
+};
+
+const gradeClassMap = {
+  miss: "grade-miss",
+  partial: "grade-partial",
+  solid: "grade-solid",
+  strong: "grade-strong",
+};
+
+function setButtonLoading(button, loadingText) {
+  button.disabled = true;
+  button.classList.add("is-loading");
+  const textEl = button.querySelector(".btn-text");
+  if (textEl && loadingText) {
+    textEl.dataset.originalText = textEl.textContent;
+    textEl.textContent = loadingText;
+  }
+}
+
+function clearButtonLoading(button) {
+  button.disabled = false;
+  button.classList.remove("is-loading");
+  const textEl = button.querySelector(".btn-text");
+  if (textEl && textEl.dataset.originalText) {
+    textEl.textContent = textEl.dataset.originalText;
+    delete textEl.dataset.originalText;
+  }
+}
+
 els.sessionForm.addEventListener("submit", async (event) => {
   event.preventDefault();
   clearError();
-  setStatus("Creating diagnostic session...");
+  setStatus("Creating diagnostic session...", true);
+  setButtonLoading(event.submitter || document.querySelector("#start-button"), "Starting...");
 
   const payload = {
     user_id: value("#user-id"),
@@ -54,6 +95,8 @@ els.sessionForm.addEventListener("submit", async (event) => {
   } catch (error) {
     showError(error.message);
     setStatus("Ready");
+  } finally {
+    clearButtonLoading(document.querySelector("#start-button"));
   }
 });
 
@@ -67,8 +110,8 @@ els.answerForm.addEventListener("submit", async (event) => {
   clearError();
   if (!state.session || !state.selectedQuestion) return;
 
-  setStatus("Submitting answer...");
-  els.answerButton.disabled = true;
+  setStatus("Submitting answer...", true);
+  setButtonLoading(event.submitter || els.answerButton, "Grading...");
 
   try {
     const answer = await request(`/api/v1/diagnostic-sessions/${state.session.id}/answers`, {
@@ -86,6 +129,7 @@ els.answerForm.addEventListener("submit", async (event) => {
     showError(error.message);
     setStatus("Session ready");
   } finally {
+    clearButtonLoading(els.answerButton);
     els.answerButton.disabled = !state.selectedQuestion;
   }
 });
@@ -93,7 +137,8 @@ els.answerForm.addEventListener("submit", async (event) => {
 els.materialForm.addEventListener("submit", async (event) => {
   event.preventDefault();
   clearError();
-  setStatus("Ingesting material...");
+  setStatus("Ingesting material...", true);
+  setButtonLoading(event.submitter || document.querySelector("#material-button"), "Ingesting...");
 
   try {
     const result = await request("/api/v1/materials", {
@@ -110,13 +155,16 @@ els.materialForm.addEventListener("submit", async (event) => {
   } catch (error) {
     showError(error.message);
     setStatus("Content workspace ready");
+  } finally {
+    clearButtonLoading(document.querySelector("#material-button"));
   }
 });
 
 els.assetForm.addEventListener("submit", async (event) => {
   event.preventDefault();
   clearError();
-  setStatus("Generating prompt candidate...");
+  setStatus("Generating prompt candidate...", true);
+  setButtonLoading(event.submitter || els.assetButton, "Generating...");
 
   try {
     const prompt = await request("/api/v1/teaching-assets/prompts", {
@@ -132,12 +180,14 @@ els.assetForm.addEventListener("submit", async (event) => {
   } catch (error) {
     showError(error.message);
     setStatus("Content workspace ready");
+  } finally {
+    clearButtonLoading(els.assetButton);
   }
 });
 
 function renderSession() {
   if (!state.session) return;
-  els.title.textContent = `${state.session.target_role} - ${state.session.questions.length} questions`;
+  els.title.textContent = `${state.session.target_role} — ${state.session.questions.length} questions`;
   els.questions.className = "question-list";
   els.questions.innerHTML = "";
 
@@ -146,7 +196,7 @@ function renderSession() {
     button.type = "button";
     button.className = "question-button";
     button.setAttribute("aria-pressed", String(state.selectedQuestion?.id === question.id));
-    button.innerHTML = `<span class="question-id">${question.id}</span>${escapeHTML(question.prompt)}`;
+    button.innerHTML = `<span class="question-id">${escapeHTML(question.id)}</span>${escapeHTML(question.prompt)}`;
     button.addEventListener("click", () => {
       state.selectedQuestion = question;
       els.answerText.value = "";
@@ -161,7 +211,7 @@ function renderSession() {
 
 async function refreshProgress() {
   if (!state.session) return;
-  setStatus("Refreshing learning progress...");
+  setStatus("Refreshing learning progress...", true);
 
   try {
     const userID = encodeURIComponent(state.session.user_id);
@@ -183,7 +233,7 @@ function renderProgress() {
   els.refreshProgress.disabled = !state.session;
   if (!state.progress) {
     els.progress.className = "feedback empty-state";
-    els.progress.textContent = "Answer once to update learner memory and readiness.";
+    els.progress.innerHTML = `<span class="empty-hint">Answer once to update learner memory and readiness.</span>`;
     return;
   }
 
@@ -197,11 +247,14 @@ function renderProgress() {
     </section>
     <section>
       <h2>Concept memory</h2>
-      <div>${mastery.map((item) => `<span class="concept-pill">${escapeHTML(item.concept.label)} - ${escapeHTML(item.state)}</span>`).join("")}</div>
+      <div>${mastery.map((item) => {
+        const cls = readinessClassMap[item.state] || "pill-neutral";
+        return `<span class="concept-pill ${cls}">${escapeHTML(item.concept.label)} — ${escapeHTML(item.state)}</span>`;
+      }).join("")}</div>
     </section>
     <section>
       <h2>Next challenge</h2>
-      <p class="status-line">${escapeHTML(challenge.concept.label)} - ${escapeHTML(challenge.ladder_level)}</p>
+      <p class="status-line">${escapeHTML(challenge.concept.label)} — ${escapeHTML(challenge.ladder_level)}</p>
       <p>${escapeHTML(challenge.question)}</p>
     </section>
   `;
@@ -210,7 +263,7 @@ function renderProgress() {
 function renderOntology() {
   if (!state.ontology) {
     els.ontology.className = "ontology-view empty-state";
-    els.ontology.textContent = "Ingest material to inspect ontology candidates.";
+    els.ontology.innerHTML = `<span class="empty-hint">Ingest material to inspect ontology candidates.</span>`;
     return;
   }
 
@@ -224,7 +277,10 @@ function renderOntology() {
     </div>
     <section>
       <h2>Candidate concepts</h2>
-      <div>${concepts.map((item) => `<span class="concept-pill">${escapeHTML(item.concept.label)} - ${escapeHTML(item.review_state)}</span>`).join("") || "No candidates yet."}</div>
+      <div>${concepts.map((item) => {
+        const cls = reviewClassMap[item.review_state] || "pill-neutral";
+        return `<span class="concept-pill ${cls}">${escapeHTML(item.concept.label)} — ${escapeHTML(item.review_state)}</span>`;
+      }).join("") || "No candidates yet."}</div>
     </section>
   `;
 
@@ -238,7 +294,7 @@ function renderOntology() {
 function renderAssetPrompt() {
   if (!state.assetPrompt) {
     els.assetOutput.className = "ontology-view empty-state";
-    els.assetOutput.textContent = "Generate a prompt to inspect model key, review state, and evidence.";
+    els.assetOutput.innerHTML = `<span class="empty-hint">Generate a prompt to inspect model key, review state, and evidence.</span>`;
     return;
   }
 
@@ -258,15 +314,16 @@ function renderAssetPrompt() {
 function renderFeedback() {
   if (!state.lastAnswer) {
     els.feedback.className = "feedback empty-state";
-    els.feedback.textContent = "Submit an answer to see grade, evidence, and follow-up.";
+    els.feedback.innerHTML = `<span class="empty-hint">Submit an answer to see grade, evidence, and follow-up.</span>`;
     return;
   }
 
   const grade = state.lastAnswer.grade;
+  const gradeClass = gradeClassMap[grade.overall] || "";
   els.feedback.className = "feedback";
   els.feedback.innerHTML = `
     <div>
-      <div class="grade">${escapeHTML(grade.overall)}</div>
+      <div class="grade ${gradeClass}">${escapeHTML(grade.overall)}</div>
       <p class="status-line">${escapeHTML(grade.strengths?.[0] || "Answer was graded.")}</p>
     </div>
     ${scoreRows(grade.scores)}
@@ -318,8 +375,11 @@ function value(selector) {
   return document.querySelector(selector).value.trim();
 }
 
-function setStatus(message) {
-  els.status.textContent = message;
+function setStatus(message, busy = false) {
+  const textEl = els.status.querySelector(".status-text");
+  if (textEl) textEl.textContent = message;
+  else els.status.textContent = message;
+  els.status.classList.toggle("is-busy", busy);
 }
 
 function showError(message) {
diff --git a/internal/webapp/static/index.html b/internal/webapp/static/index.html
index e07d4dc..e957d4c 100644
--- a/internal/webapp/static/index.html
+++ b/internal/webapp/static/index.html
@@ -30,26 +30,37 @@
             Timeline
             <input id="timeline" name="interview_timeline" value="30 days" />
           </label>
-          <button id="start-button" type="submit">Start diagnostic</button>
+          <button id="start-button" type="submit">
+            <span class="btn-text">Start diagnostic</span>
+            <span class="btn-spinner" aria-hidden="true"></span>
+          </button>
         </form>
 
-        <p id="status-line" class="status-line" role="status">Ready</p>
+        <p id="status-line" class="status-line" role="status">
+          <span class="status-icon" aria-hidden="true"></span>
+          <span class="status-text">Ready</span>
+        </p>
         <p id="error-line" class="error-line" role="alert"></p>
       </aside>
 
       <section class="practice-pane" aria-label="Diagnostic practice">
         <div class="section-heading">
-          <p class="eyebrow">Diagnostic</p>
-          <h2 id="session-title">No active session</h2>
+          <div>
+            <p class="eyebrow">Diagnostic</p>
+            <h2 id="session-title">No active session</h2>
+          </div>
         </div>
         <div id="questions" class="question-list empty-state">
-          Start a diagnostic session to load interview questions.
+          <span class="empty-hint">Start a diagnostic session to load interview questions.</span>
         </div>
 
         <form id="answer-form" class="answer-form">
           <label for="answer-text">Answer</label>
           <textarea id="answer-text" rows="7" placeholder="Select a question, then answer with concrete production reasoning."></textarea>
-          <button id="answer-button" type="submit" disabled>Submit answer</button>
+          <button id="answer-button" type="submit" disabled>
+            <span class="btn-text">Submit answer</span>
+            <span class="btn-spinner" aria-hidden="true"></span>
+          </button>
         </form>
 
         <section class="content-workspace" aria-label="Material and asset workspace">
@@ -73,17 +84,22 @@
               Source material
               <textarea id="material-body" rows="5">Idempotent API retries need transactions. Cache invalidation uses TTL tradeoffs and database indexes support query plans.</textarea>
             </label>
-            <button id="material-button" type="submit">Ingest material</button>
+            <button id="material-button" type="submit">
+              <span class="btn-text">Ingest material</span>
+              <span class="btn-spinner" aria-hidden="true"></span>
+            </button>
           </form>
 
           <div id="ontology" class="ontology-view empty-state">
-            Ingest material to inspect ontology candidates.
+            <span class="empty-hint">Ingest material to inspect ontology candidates.</span>
           </div>
 
           <form id="asset-form" class="asset-form">
             <label>
               Concept
-              <select id="asset-concept" disabled></select>
+              <select id="asset-concept" disabled>
+                <option value="">Select a concept</option>
+              </select>
             </label>
             <label>
               Asset type
@@ -94,22 +110,27 @@
                 <option value="interview_card">Interview card</option>
               </select>
             </label>
-            <button id="asset-button" type="submit" disabled>Generate prompt</button>
+            <button id="asset-button" type="submit" disabled>
+              <span class="btn-text">Generate prompt</span>
+              <span class="btn-spinner" aria-hidden="true"></span>
+            </button>
           </form>
 
           <div id="asset-output" class="ontology-view empty-state">
-            Generate a prompt to inspect model key, review state, and evidence.
+            <span class="empty-hint">Generate a prompt to inspect model key, review state, and evidence.</span>
           </div>
         </section>
       </section>
 
       <aside class="feedback-pane" aria-label="Feedback">
         <div class="section-heading">
-          <p class="eyebrow">Feedback</p>
-          <h2>Rubric result</h2>
+          <div>
+            <p class="eyebrow">Feedback</p>
+            <h2>Rubric result</h2>
+          </div>
         </div>
         <div id="feedback" class="feedback empty-state">
-          Submit an answer to see grade, evidence, and follow-up.
+          <span class="empty-hint">Submit an answer to see grade, evidence, and follow-up.</span>
         </div>
         <div class="section-heading progress-heading">
           <div>
@@ -119,7 +140,7 @@
           <button id="refresh-progress" class="small-button" type="button" disabled>Refresh</button>
         </div>
         <div id="progress" class="feedback empty-state">
-          Answer once to update learner memory and readiness.
+          <span class="empty-hint">Answer once to update learner memory and readiness.</span>
         </div>
       </aside>
     </main>
diff --git a/internal/webapp/static/styles.css b/internal/webapp/static/styles.css
index 12ec64d..72d613a 100644
--- a/internal/webapp/static/styles.css
+++ b/internal/webapp/static/styles.css
@@ -9,6 +9,16 @@
   --accent: #19764b;
   --accent-dark: #105c39;
   --danger: #a93a2f;
+  --warn: #b45f1a;
+  --warn-bg: #fff6eb;
+  --weak: #a93a2f;
+  --weak-bg: #fdf2f1;
+  --good: #1a6b8f;
+  --good-bg: #eef7fb;
+  --strong: #19764b;
+  --strong-bg: #f0faf3;
+  --neutral: #6b7570;
+  --neutral-bg: #f4f5f4;
 }
 
 * {
@@ -22,6 +32,8 @@ body {
   color: var(--text);
   font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
   letter-spacing: 0;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
 }
 
 button,
@@ -57,7 +69,12 @@ select {
   color: var(--accent);
   font-size: 12px;
   font-weight: 750;
-  text-transform: uppercase;
+  letter-spacing: 0.06em;
+}
+
+html[lang="ko"] .eyebrow {
+  text-transform: none;
+  letter-spacing: 0.02em;
 }
 
 h1,
@@ -67,8 +84,8 @@ h2 {
 }
 
 h1 {
-  max-width: 9ch;
-  font-size: clamp(42px, 6vw, 74px);
+  font-size: clamp(36px, 5vw, 64px);
+  line-height: 1.05;
 }
 
 h2 {
@@ -118,6 +135,14 @@ select {
   color: var(--text);
   padding: 12px;
   outline: none;
+  appearance: none;
+}
+
+select {
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%235b665f' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
+  background-repeat: no-repeat;
+  background-position: right 12px center;
+  padding-right: 36px;
 }
 
 textarea {
@@ -141,29 +166,86 @@ button {
   color: #fff;
   cursor: pointer;
   font-weight: 750;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  position: relative;
 }
 
 button:hover:not(:disabled) {
   background: var(--accent-dark);
 }
 
+button:active:not(:disabled) {
+  transform: translateY(1px);
+}
+
 button:disabled {
   cursor: not-allowed;
   opacity: 0.48;
 }
 
-.status-line,
-.error-line {
-  min-height: 20px;
-  margin: 18px 0 0;
-  font-size: 13px;
+.btn-spinner {
+  display: none;
+  width: 16px;
+  height: 16px;
+  border: 2px solid rgba(255, 255, 255, 0.35);
+  border-top-color: #fff;
+  border-radius: 50%;
+  animation: spin 0.8s linear infinite;
+}
+
+button.is-loading .btn-text {
+  opacity: 0.9;
+}
+
+button.is-loading .btn-spinner {
+  display: inline-block;
+}
+
+@keyframes spin {
+  to {
+    transform: rotate(360deg);
+  }
 }
 
 .status-line {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  min-height: 20px;
+  margin: 18px 0 0;
+  font-size: 13px;
   color: var(--muted);
 }
 
+.status-icon {
+  display: inline-block;
+  width: 8px;
+  height: 8px;
+  border-radius: 50%;
+  background: var(--accent);
+}
+
+.status-line.is-busy .status-icon {
+  background: var(--warn);
+  animation: pulse 1.2s ease-in-out infinite;
+}
+
+@keyframes pulse {
+  0%, 100% {
+    opacity: 1;
+  }
+  50% {
+    opacity: 0.35;
+  }
+}
+
 .error-line {
+  min-height: 20px;
+  margin: 10px 0 0;
+  font-size: 13px;
   color: var(--danger);
 }
 
@@ -181,15 +263,23 @@ button:disabled {
 
 .question-button {
   border: 1px solid var(--line);
+  border-left: 3px solid transparent;
   background: #fbfcfa;
   color: var(--text);
   padding: 16px;
   min-height: 72px;
   text-align: left;
+  border-radius: 6px;
+  transition: border-color 0.15s ease, background 0.15s ease;
+}
+
+.question-button:hover:not(:disabled) {
+  border-color: var(--accent);
 }
 
 .question-button[aria-pressed="true"] {
   border-color: var(--accent);
+  border-left-color: var(--accent);
   background: var(--surface-muted);
 }
 
@@ -205,7 +295,21 @@ button:disabled {
   border: 1px dashed var(--line);
   border-radius: 6px;
   color: var(--muted);
-  padding: 18px;
+  padding: 22px 18px;
+  text-align: center;
+  font-size: 13px;
+  line-height: 1.5;
+}
+
+.empty-hint::before {
+  content: "";
+  display: block;
+  width: 24px;
+  height: 24px;
+  margin: 0 auto 10px;
+  opacity: 0.45;
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%235b665f' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Ccircle cx='12' cy='12' r='10'/%3E%3Cpath d='M12 16v-4'/%3E%3Cpath d='M12 8h.01'/%3E%3C/svg%3E");
+  background-size: contain;
 }
 
 .feedback {
@@ -232,10 +336,30 @@ button:disabled {
   border-bottom: 1px solid var(--line);
 }
 
+.metric-row:last-child {
+  border-bottom: 0;
+}
+
 .grade {
-  color: var(--accent);
   font-size: 38px;
   font-weight: 800;
+  line-height: 1.1;
+}
+
+.grade-miss {
+  color: var(--weak);
+}
+
+.grade-partial {
+  color: var(--warn);
+}
+
+.grade-solid {
+  color: var(--good);
+}
+
+.grade-strong {
+  color: var(--strong);
 }
 
 .readiness-value {
@@ -250,10 +374,41 @@ button:disabled {
   margin: 4px 6px 4px 0;
   border: 1px solid var(--line);
   border-radius: 999px;
-  padding: 6px 9px;
+  padding: 6px 10px;
   color: var(--muted);
   font-size: 12px;
   font-weight: 650;
+  background: var(--surface);
+}
+
+.pill-neutral {
+  background: var(--neutral-bg);
+  border-color: #d5dad3;
+  color: var(--neutral);
+}
+
+.pill-weak {
+  background: var(--weak-bg);
+  border-color: #e8bdb9;
+  color: var(--weak);
+}
+
+.pill-warn {
+  background: var(--warn-bg);
+  border-color: #edd5b5;
+  color: var(--warn);
+}
+
+.pill-good {
+  background: var(--good-bg);
+  border-color: #b8d9e8;
+  color: var(--good);
+}
+
+.pill-strong {
+  background: var(--strong-bg);
+  border-color: #b8dfc6;
+  color: var(--strong);
 }
 
 .small-list {
@@ -264,10 +419,11 @@ button:disabled {
 }
 
 .content-workspace {
-  border-top: 1px solid var(--line);
+  border-top: 2px solid var(--line);
   display: grid;
   gap: 18px;
-  padding-top: 24px;
+  padding-top: 28px;
+  margin-top: 6px;
 }
 
 .ontology-view {
@@ -283,11 +439,11 @@ button:disabled {
 
 .summary-chip {
   background: var(--surface-muted);
-  border-radius: 6px;
+  border-radius: 999px;
   color: var(--muted);
   font-size: 12px;
   font-weight: 750;
-  padding: 9px 11px;
+  padding: 7px 12px;
 }
 
 .prompt-text {
@@ -297,6 +453,9 @@ button:disabled {
   margin: 0;
   padding: 14px;
   white-space: pre-wrap;
+  font-size: 13px;
+  line-height: 1.5;
+  color: var(--text);
 }
 
 @media (max-width: 980px) {
@@ -305,7 +464,6 @@ button:disabled {
   }
 
   h1 {
-    max-width: 100%;
     font-size: 42px;
   }