diff --git a/2016/src/App.css b/2016/src/App.css
index dc235f3..9410c19 100644
--- a/2016/src/App.css
+++ b/2016/src/App.css
@@ -1,24 +1,38 @@
 .app {
   max-width: 1200px;
   margin: 0 auto;
-  padding: 2rem 1rem;
-  font-family: system-ui, -apple-system, sans-serif;
+  padding: 2rem 1rem 3rem;
 }
 
+/* Header */
 header {
   text-align: center;
   margin-bottom: 2rem;
 }
 
 header h1 {
-  font-size: 1.8rem;
-  color: #1a1a2e;
-  margin-bottom: 0.25rem;
+  font-size: clamp(1.4rem, 2.4vw, 2rem);
+  color: var(--text);
+  margin: 0 0 0.4rem;
+  letter-spacing: -0.01em;
+  font-weight: 700;
 }
 
 .subtitle {
-  color: #666;
+  color: var(--text-muted);
   font-size: 0.95rem;
+  margin: 0;
+}
+
+.subtitle .pill {
+  display: inline-block;
+  padding: 0.1rem 0.55rem;
+  background: var(--accent-soft);
+  color: var(--accent);
+  border-radius: 999px;
+  font-weight: 600;
+  font-size: 0.8rem;
+  margin-right: 0.35rem;
 }
 
 /* Tabs */
@@ -27,29 +41,30 @@ header h1 {
   gap: 0;
   max-width: 600px;
   margin: 0 auto 1.5rem;
-  border-bottom: 2px solid #ddd;
+  border-bottom: 1px solid var(--border);
 }
 
 .tab {
   flex: 1;
   padding: 0.75rem 1rem;
-  font-size: 1rem;
+  font-size: 0.95rem;
   background: none;
   border: none;
   border-bottom: 2px solid transparent;
-  margin-bottom: -2px;
+  margin-bottom: -1px;
   cursor: pointer;
-  color: #666;
-  transition: color 0.2s, border-color 0.2s;
+  color: var(--text-muted);
+  font-weight: 500;
+  transition: color 0.15s, border-color 0.15s;
 }
 
 .tab:hover {
-  color: #4361ee;
+  color: var(--accent);
 }
 
-.tab.active {
-  color: #4361ee;
-  border-bottom-color: #4361ee;
+.tab[aria-selected="true"] {
+  color: var(--accent);
+  border-bottom-color: var(--accent);
   font-weight: 600;
 }
 
@@ -59,35 +74,71 @@ header h1 {
   gap: 0.5rem;
   max-width: 600px;
   margin: 0 auto 1.5rem;
+  position: relative;
+}
+
+.search-field {
+  flex: 1;
+  position: relative;
 }
 
 .search-form input {
-  flex: 1;
-  padding: 0.75rem 1rem;
+  width: 100%;
+  padding: 0.75rem 2.25rem 0.75rem 1rem;
   font-size: 1rem;
-  border: 2px solid #ddd;
-  border-radius: 8px;
+  border: 1px solid var(--border-strong);
+  border-radius: var(--radius);
+  background: var(--surface);
+  color: var(--text);
   outline: none;
-  transition: border-color 0.2s;
+  transition: border-color 0.15s, box-shadow 0.15s;
 }
 
 .search-form input:focus {
-  border-color: #4361ee;
+  border-color: var(--accent);
+  box-shadow: 0 0 0 3px var(--accent-soft);
 }
 
-.search-form button {
-  padding: 0.75rem 1.5rem;
-  font-size: 1rem;
-  background: #4361ee;
-  color: white;
+.search-clear {
+  position: absolute;
+  right: 0.4rem;
+  top: 50%;
+  transform: translateY(-50%);
+  width: 1.75rem;
+  height: 1.75rem;
+  display: grid;
+  place-items: center;
   border: none;
-  border-radius: 8px;
+  background: transparent;
+  color: var(--text-faint);
+  font-size: 1.1rem;
+  border-radius: 50%;
   cursor: pointer;
-  transition: background 0.2s;
 }
 
-.search-form button:hover:not(:disabled) {
-  background: #3a56d4;
+.search-clear:hover {
+  background: var(--surface-alt);
+  color: var(--text);
+}
+
+.search-form button[type="submit"] {
+  padding: 0.75rem 1.5rem;
+  font-size: 0.95rem;
+  font-weight: 600;
+  background: var(--accent);
+  color: #fff;
+  border: none;
+  border-radius: var(--radius);
+  cursor: pointer;
+  transition: background 0.15s, transform 0.05s;
+}
+
+.search-form button[type="submit"]:hover:not(:disabled) {
+  background: var(--accent-hover);
+}
+
+.search-form button[type="submit"]:active:not(:disabled) {
+  transform: translateY(1px);
 }
 
 .search-form button:disabled {
@@ -97,37 +148,41 @@ header h1 {
 
 /* Custom query */
 .custom-query {
-  max-width: 900px;
+  max-width: 960px;
   margin: 0 auto;
 }
 
 .preset-list {
   display: flex;
   flex-wrap: wrap;
-  gap: 0.5rem;
-  margin-bottom: 1rem;
+  gap: 0.4rem;
+  margin-bottom: 0.85rem;
   align-items: center;
 }
 
 .preset-label {
-  font-size: 0.85rem;
-  color: #666;
+  font-size: 0.8rem;
+  color: var(--text-muted);
   white-space: nowrap;
+  margin-right: 0.25rem;
+  font-weight: 500;
 }
 
 .preset-btn {
   padding: 0.35rem 0.75rem;
   font-size: 0.8rem;
-  background: #f0f0f5;
-  border: 1px solid #ddd;
-  border-radius: 6px;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  color: var(--text);
+  border-radius: 999px;
   cursor: pointer;
-  transition: background 0.2s, border-color 0.2s;
+  transition: background 0.15s, border-color 0.15s, color 0.15s;
 }
 
 .preset-btn:hover:not(:disabled) {
-  background: #e8e8f0;
-  border-color: #4361ee;
+  background: var(--accent-soft);
+  border-color: var(--accent);
+  color: var(--accent);
 }
 
 .preset-btn:disabled {
@@ -141,42 +196,49 @@ header h1 {
 
 .query-form textarea {
   width: 100%;
-  padding: 0.75rem 1rem;
+  padding: 0.85rem 1rem;
   font-size: 0.9rem;
-  font-family: "Cascadia Code", "Fira Code", "JetBrains Mono", monospace;
-  border: 2px solid #ddd;
-  border-radius: 8px;
+  font-family:
+    "JetBrains Mono", "Cascadia Code", "Fira Code", ui-monospace, monospace;
+  background: var(--surface);
+  color: var(--text);
+  border: 1px solid var(--border-strong);
+  border-radius: var(--radius);
   outline: none;
   resize: vertical;
-  min-height: 120px;
-  transition: border-color 0.2s;
+  min-height: 130px;
+  transition: border-color 0.15s, box-shadow 0.15s;
   tab-size: 2;
+  line-height: 1.5;
 }
 
 .query-form textarea:focus {
-  border-color: #4361ee;
+  border-color: var(--accent);
+  box-shadow: 0 0 0 3px var(--accent-soft);
 }
 
 .query-actions {
   display: flex;
   align-items: center;
   gap: 1rem;
-  margin-top: 0.5rem;
+  margin-top: 0.6rem;
+  flex-wrap: wrap;
 }
 
 .query-actions button {
-  padding: 0.6rem 1.5rem;
-  font-size: 0.95rem;
-  background: #4361ee;
-  color: white;
+  padding: 0.6rem 1.4rem;
+  font-size: 0.9rem;
+  font-weight: 600;
+  background: var(--accent);
+  color: #fff;
   border: none;
-  border-radius: 8px;
+  border-radius: var(--radius);
   cursor: pointer;
-  transition: background 0.2s;
+  transition: background 0.15s;
 }
 
 .query-actions button:hover:not(:disabled) {
-  background: #3a56d4;
+  background: var(--accent-hover);
 }
 
 .query-actions button:disabled {
@@ -186,28 +248,57 @@ header h1 {
 
 .exec-time {
   font-size: 0.85rem;
-  color: #666;
+  color: var(--text-muted);
+  font-variant-numeric: tabular-nums;
+}
+
+.exec-time.running {
+  color: var(--accent);
+}
+
+.kbd {
+  display: inline-block;
+  padding: 0.05rem 0.4rem;
+  font-family: ui-monospace, monospace;
+  font-size: 0.75rem;
+  background: var(--surface-alt);
+  border: 1px solid var(--border);
+  border-bottom-width: 2px;
+  border-radius: 4px;
+  color: var(--text-muted);
 }
 
 /* Loading */
 .loading {
+  max-width: 600px;
+  margin: 0.5rem auto 1.5rem;
+  padding: 0.85rem 1rem;
   text-align: center;
-  margin: 1rem 0;
-  color: #555;
+  color: var(--text-muted);
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius);
+  box-shadow: var(--shadow-sm);
+}
+
+.loading p {
+  margin: 0 0 0.5rem;
+  font-size: 0.9rem;
 }
 
 .progress-bar {
-  width: 300px;
-  height: 8px;
-  background: #eee;
+  width: 100%;
+  max-width: 300px;
+  height: 6px;
+  background: var(--surface-alt);
   border-radius: 4px;
-  margin: 0.5rem auto;
+  margin: 0 auto;
   overflow: hidden;
 }
 
 .progress-fill {
   height: 100%;
-  background: #4361ee;
+  background: linear-gradient(90deg, var(--accent), var(--accent-hover));
   border-radius: 4px;
   transition: width 0.3s;
 }
@@ -216,12 +307,17 @@ header h1 {
 .table-wrapper {
   overflow-x: auto;
   margin-top: 1rem;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius);
+  box-shadow: var(--shadow-sm);
 }
 
 .result-count {
-  color: #555;
+  color: var(--text-muted);
   font-size: 0.9rem;
-  margin-bottom: 0.5rem;
+  margin: 0.5rem 0;
+  padding: 0 0.25rem;
 }
 
 table {
@@ -231,31 +327,53 @@ table {
 }
 
 thead th {
-  background: #f0f0f5;
-  padding: 0.6rem 0.5rem;
+  background: var(--surface-alt);
+  padding: 0.65rem 0.6rem;
   text-align: left;
   white-space: nowrap;
   position: sticky;
   top: 0;
-  border-bottom: 2px solid #ddd;
+  border-bottom: 1px solid var(--border-strong);
+  color: var(--text-muted);
+  font-weight: 600;
+  font-size: 0.8rem;
+  text-transform: uppercase;
+  letter-spacing: 0.03em;
 }
 
 tbody td {
-  padding: 0.5rem;
-  border-bottom: 1px solid #eee;
+  padding: 0.55rem 0.6rem;
+  border-bottom: 1px solid var(--border);
 }
 
-tbody tr:hover {
-  background: #f8f9ff;
+tbody tr:last-child td {
+  border-bottom: none;
+}
+
+tbody tr:nth-child(even) td {
+  background: color-mix(in srgb, var(--surface-alt) 45%, transparent);
+}
+
+tbody tr:hover td {
+  background: var(--accent-soft);
+}
+
+.sbd-cell {
+  font-family: ui-monospace, monospace;
+  font-size: 0.85rem;
+  color: var(--text-muted);
+  white-space: nowrap;
 }
 
 .name-cell {
   white-space: nowrap;
+  font-weight: 500;
 }
 
 .cumthi-cell {
-  font-size: 0.8rem;
-  max-width: 200px;
+  font-size: 0.82rem;
+  color: var(--text-muted);
+  max-width: 220px;
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
@@ -266,30 +384,46 @@ tbody tr:hover {
   font-variant-numeric: tabular-nums;
 }
 
+.score-cell.score-high {
+  color: var(--ok);
+  font-weight: 600;
+}
+
+.score-cell.score-low {
+  color: var(--danger);
+}
+
+.score-cell.score-empty {
+  color: var(--text-faint);
+}
+
 /* Messages */
 .no-results,
 .error,
 .warning {
   text-align: center;
-  padding: 1rem;
-  border-radius: 8px;
-  margin: 1rem 0;
+  padding: 0.9rem 1rem;
+  border-radius: var(--radius);
+  margin: 1rem auto;
+  max-width: 600px;
+  font-size: 0.9rem;
 }
 
 .no-results {
-  color: #666;
-  background: #f5f5f5;
+  color: var(--text-muted);
+  background: var(--surface);
+  border: 1px dashed var(--border-strong);
 }
 
 .error {
-  color: #d32f2f;
-  background: #fdecea;
+  color: var(--danger);
+  background: var(--danger-bg);
+  border: 1px solid color-mix(in srgb, var(--danger) 25%, transparent);
 }
 
 .warning {
-  color: #e65100;
-  background: #fff3e0;
-  font-size: 0.9rem;
+  color: var(--warn);
+  background: var(--warn-bg);
 }
 
 /* Footer */
@@ -297,27 +431,44 @@ footer {
   text-align: center;
   margin-top: 3rem;
   padding-top: 1rem;
-  border-top: 1px solid #eee;
-  color: #999;
+  border-top: 1px solid var(--border);
+  color: var(--text-faint);
   font-size: 0.85rem;
 }
 
+footer a {
+  color: var(--text-muted);
+}
+
 /* Responsive */
-@media (max-width: 600px) {
-  header h1 {
-    font-size: 1.3rem;
+@media (max-width: 640px) {
+  .app {
+    padding: 1.25rem 0.75rem 2rem;
   }
 
   .search-form {
     flex-direction: column;
   }
 
+  .search-form button[type="submit"] {
+    width: 100%;
+  }
+
   table {
     font-size: 0.8rem;
   }
 
+  thead th,
+  tbody td {
+    padding: 0.45rem 0.4rem;
+  }
+
   .preset-list {
     flex-direction: column;
-    align-items: flex-start;
+    align-items: stretch;
+  }
+
+  .preset-btn {
+    text-align: left;
   }
 }
diff --git a/2016/src/App.jsx b/2016/src/App.jsx
index f09e734..494519c 100644
--- a/2016/src/App.jsx
+++ b/2016/src/App.jsx
@@ -93,16 +93,16 @@ function App() {
       <header>
         <h1>Tra cứu điểm thi THPT Quốc gia 2016</h1>
         <p className="subtitle">
-          Dữ liệu 877.461 thí sinh toàn quốc · Hỗ trợ truy vấn SQL tùy chỉnh
+          <span className="pill">877.461 thí sinh</span>
+          Dữ liệu toàn quốc · Hỗ trợ truy vấn SQL tùy chỉnh
         </p>
       </header>
 
       <main>
         {loading && (
-          <div className="loading">
+          <div className="loading" role="status" aria-live="polite">
             <p>
-              Đang tải cơ sở dữ liệu...{" "}
-              {progress > 0 ? `${progress}%` : ""}
+              Đang tải cơ sở dữ liệu{progress > 0 ? ` · ${progress}%` : "..."}
             </p>
             <div className="progress-bar">
               <div
@@ -115,15 +115,19 @@ function App() {
 
         {error && <p className="error">Lỗi: {error}</p>}
 
-        <div className="tabs">
+        <div className="tabs" role="tablist">
           <button
-            className={`tab ${activeTab === "search" ? "active" : ""}`}
+            role="tab"
+            aria-selected={activeTab === "search"}
+            className="tab"
             onClick={() => setActiveTab("search")}
           >
             Tra cứu
           </button>
           <button
-            className={`tab ${activeTab === "sql" ? "active" : ""}`}
+            role="tab"
+            aria-selected={activeTab === "sql"}
+            className="tab"
             onClick={() => setActiveTab("sql")}
           >
             Truy vấn SQL
diff --git a/2016/src/components/custom-query.jsx b/2016/src/components/custom-query.jsx
index 0c14548..5b4ed01 100644
--- a/2016/src/components/custom-query.jsx
+++ b/2016/src/components/custom-query.jsx
@@ -172,7 +172,8 @@ export function CustomQuery({ db, disabled }) {
         />
         <div className="query-actions">
           <button type="submit" disabled={disabled || !sql.trim()}>
-            Thực thi (Ctrl+Enter)
+            Thực thi <span className="kbd">Ctrl</span>+
+            <span className="kbd">Enter</span>
           </button>
           {execTime !== null && (
             <span className="exec-time">
diff --git a/2016/src/components/score-table.jsx b/2016/src/components/score-table.jsx
index 5ddd1fc..e5258d6 100644
--- a/2016/src/components/score-table.jsx
+++ b/2016/src/components/score-table.jsx
@@ -18,6 +18,14 @@ function formatScore(val) {
   return Number(val).toFixed(2);
 }
 
+function scoreClass(val) {
+  if (val === null || val === undefined) return "score-cell score-empty";
+  const num = Number(val);
+  if (num >= 8) return "score-cell score-high";
+  if (num < 4) return "score-cell score-low";
+  return "score-cell";
+}
+
 export function ScoreTable({ results }) {
   if (!results) return null;
   if (results.length === 0) {
@@ -25,38 +33,42 @@ export function ScoreTable({ results }) {
   }
 
   return (
-    <div className="table-wrapper">
+    <>
       <p className="result-count">Tìm thấy {results.length} kết quả</p>
-      <table>
-        <thead>
-          <tr>
-            <th>SBD</th>
-            <th>Họ tên</th>
-            <th>Ngày sinh</th>
-            <th>Cụm thi</th>
-            <th>GT</th>
-            {SUBJECT_COLUMNS.map((col) => (
-              <th key={col.key}>{col.label}</th>
-            ))}
-          </tr>
-        </thead>
-        <tbody>
-          {results.map((row) => (
-            <tr key={row.so_bao_danh}>
-              <td>{row.so_bao_danh}</td>
-              <td className="name-cell">{row.ho_ten}</td>
-              <td>{row.ngay_sinh || "—"}</td>
-              <td className="cumthi-cell">{row.ten_cum_thi || "—"}</td>
-              <td>{row.gioi_tinh || "—"}</td>
+      <div className="table-wrapper">
+        <table>
+          <thead>
+            <tr>
+              <th>SBD</th>
+              <th>Họ tên</th>
+              <th>Ngày sinh</th>
+              <th>Cụm thi</th>
+              <th>GT</th>
               {SUBJECT_COLUMNS.map((col) => (
-                <td key={col.key} className="score-cell">
-                  {formatScore(row[col.key])}
-                </td>
+                <th key={col.key}>{col.label}</th>
               ))}
             </tr>
-          ))}
-        </tbody>
-      </table>
-    </div>
+          </thead>
+          <tbody>
+            {results.map((row) => (
+              <tr key={row.so_bao_danh}>
+                <td className="sbd-cell">{row.so_bao_danh}</td>
+                <td className="name-cell">{row.ho_ten}</td>
+                <td>{row.ngay_sinh || "—"}</td>
+                <td className="cumthi-cell" title={row.ten_cum_thi || ""}>
+                  {row.ten_cum_thi || "—"}
+                </td>
+                <td>{row.gioi_tinh || "—"}</td>
+                {SUBJECT_COLUMNS.map((col) => (
+                  <td key={col.key} className={scoreClass(row[col.key])}>
+                    {formatScore(row[col.key])}
+                  </td>
+                ))}
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      </div>
+    </>
   );
 }
diff --git a/2016/src/components/search-form.jsx b/2016/src/components/search-form.jsx
index 7fcbbe4..bec23f7 100644
--- a/2016/src/components/search-form.jsx
+++ b/2016/src/components/search-form.jsx
@@ -10,15 +10,34 @@ export function SearchForm({ onSearch, disabled }) {
   }
 
   return (
-    <form onSubmit={handleSubmit} className="search-form">
-      <input
-        type="text"
-        value={query}
-        onChange={(e) => setQuery(e.target.value)}
-        placeholder="Nhập SBD hoặc họ tên (VD: nguyen van a)..."
-        disabled={disabled}
-        autoFocus
-      />
+    <form onSubmit={handleSubmit} className="search-form" role="search">
+      <div className="search-field">
+        <label htmlFor="search-input" className="visually-hidden" hidden>
+          Tìm theo số báo danh hoặc họ tên
+        </label>
+        <input
+          id="search-input"
+          type="text"
+          value={query}
+          onChange={(e) => setQuery(e.target.value)}
+          placeholder="Nhập SBD hoặc họ tên (VD: nguyen van a)..."
+          disabled={disabled}
+          autoFocus
+          autoComplete="off"
+          spellCheck={false}
+        />
+        {query && (
+          <button
+            type="button"
+            className="search-clear"
+            onClick={() => setQuery("")}
+            aria-label="Xóa từ khóa"
+            tabIndex={-1}
+          >
+            ×
+          </button>
+        )}
+      </div>
       <button type="submit" disabled={disabled || !query.trim()}>
         Tra cứu
       </button>
diff --git a/2016/src/index.css b/2016/src/index.css
index 85687aa..52bc39d 100644
--- a/2016/src/index.css
+++ b/2016/src/index.css
@@ -1,13 +1,74 @@
+:root {
+  /* Light theme tokens */
+  --bg: #f7f8fb;
+  --surface: #ffffff;
+  --surface-alt: #f2f4f9;
+  --border: #e3e6ee;
+  --border-strong: #cfd4e1;
+  --text: #1a1a2e;
+  --text-muted: #5c6275;
+  --text-faint: #8a8fa3;
+  --accent: #4361ee;
+  --accent-hover: #3a56d4;
+  --accent-soft: #e9edff;
+  --danger: #d32f2f;
+  --danger-bg: #fdecea;
+  --warn: #b45309;
+  --warn-bg: #fff4d6;
+  --ok: #0f8a4f;
+  --ok-bg: #e4f7ec;
+  --shadow-sm: 0 1px 2px rgba(20, 22, 38, 0.06);
+  --shadow-md: 0 4px 14px rgba(20, 22, 38, 0.08);
+  --radius: 10px;
+  --radius-sm: 6px;
+}
+
+@media (prefers-color-scheme: dark) {
+  :root {
+    --bg: #0f1117;
+    --surface: #181b24;
+    --surface-alt: #21252f;
+    --border: #2a2f3d;
+    --border-strong: #3a4052;
+    --text: #eef0f6;
+    --text-muted: #a7adbe;
+    --text-faint: #6e7486;
+    --accent: #8aa1ff;
+    --accent-hover: #a6b8ff;
+    --accent-soft: #1e2647;
+    --danger: #ff7a7a;
+    --danger-bg: #3a1d1d;
+    --warn: #ffc875;
+    --warn-bg: #3a2a12;
+    --ok: #6ee2a4;
+    --ok-bg: #133524;
+    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
+    --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.4);
+  }
+}
+
 *,
 *::before,
 *::after {
   box-sizing: border-box;
 }
 
+html {
+  color-scheme: light dark;
+}
+
 body {
   margin: 0;
-  font-family: system-ui, -apple-system, sans-serif;
+  font-family:
+    "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
   -webkit-font-smoothing: antialiased;
-  background: #fafafa;
-  color: #333;
+  background: var(--bg);
+  color: var(--text);
+  line-height: 1.5;
+}
+
+:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+  border-radius: 4px;
 }