🎨 Palette: Improve accessibility of icon-only buttons and toggles

Co-authored-by: alvin000009238 <107313913+alvin000009238@users.noreply.github.com>

Author: google-labs-jules[bot]

frontend/sync.js

@@ -272,9 +272,13 @@ export function setupSyncFeature() {
             if (type === 'text') {
                 eyeIcon.style.display = 'none';
                 eyeOffIcon.style.display = 'block';
+                togglePasswordBtn.setAttribute('aria-label', '隱藏密碼');
+                togglePasswordBtn.setAttribute('title', '隱藏密碼');
             } else {
                 eyeIcon.style.display = 'block';
                 eyeOffIcon.style.display = 'none';
+                togglePasswordBtn.setAttribute('aria-label', '顯示密碼');
+                togglePasswordBtn.setAttribute('title', '顯示密碼');
             }
         });
     }

public/index.html

@@ -102,7 +102,7 @@ <h3>
                         <span class="material-symbols-outlined" style="font-size: 24px;">share</span>
                         分享成績單
                     </h3>
-                    <button class="modal-close" id="closeShareModal">&times;</button>
+                    <button class="modal-close" id="closeShareModal" aria-label="關閉視窗">&times;</button>
                 </div>
                 <div class="modal-body">
                     <div id="sharePreview"></div>
@@ -116,10 +116,10 @@ <h3>
                 <div class="modal-header">
                     <h3 style="display: flex; align-items: center; gap: 8px;">
                         登入系統
-                        <span class="material-symbols-outlined tooltip-icon" tabindex="0"
+                        <span class="material-symbols-outlined tooltip-icon" tabindex="0" aria-label="提示說明" role="button"
                             data-tooltip="請使用欣河校園平台帳密登入">help</span>
                     </h3>
-                    <button class="modal-close" id="closeLoginModal">&times;</button>
+                    <button class="modal-close" id="closeLoginModal" aria-label="關閉視窗">&times;</button>
                 </div>
                 <div class="modal-body">
                     <form id="loginForm" method="post" action="javascript:void(0);">
@@ -133,7 +133,7 @@ <h3 style="display: flex; align-items: center; gap: 8px;">
                                 <input type="password" id="passwordInput" name="password"
                                     autocomplete="current-password" placeholder=" ">
                                 <label>密碼</label>
-                                <button type="button" id="togglePasswordBtn" class="toggle-password-btn" tabindex="-1">
+                                <button type="button" id="togglePasswordBtn" class="toggle-password-btn" aria-label="顯示密碼" title="顯示密碼">
                                     <span class="material-symbols-outlined eye-icon">visibility</span>
                                     <span class="material-symbols-outlined eye-off-icon"
                                         style="display: none;">visibility_off</span>
@@ -160,7 +160,7 @@ <h3 style="display: flex; align-items: center; gap: 8px;">
             <div class="modal-content sm">
                 <div class="modal-header">
                     <h3>選擇考試</h3>
-                    <button class="modal-close" id="closeSelectModal">&times;</button>
+                    <button class="modal-close" id="closeSelectModal" aria-label="關閉視窗">&times;</button>
                 </div>
                 <div class="modal-body">
                     <div class="form-group">