diff --git a/src/jsMain/resources/index.html b/src/jsMain/resources/index.html
index 3a3f820..91cd122 100644
--- a/src/jsMain/resources/index.html
+++ b/src/jsMain/resources/index.html
@@ -46,7 +46,7 @@
 <div id="main">
     <div class="flex-horizontal">
         <div id="toplinks">
-            <span class="svg-icon-holder" id="btn-toggle-theme">
+            <span class="svg-icon-holder" id="btn-toggle-theme" title="Toggle theme (light/dark)">
                 <svg viewBox="0 0 512 512" xmlns="http://www.w3.org/2000/svg"><g><path
                         d="m271.102 408.674c-10.759 2.896-21.518 4.364-31.976 4.364-67.78 0-122.924-55.143-122.924-122.923 0-20.075 4.751-39.286 14.123-57.099 2.776-5.277 2.163-11.697-1.562-16.354-3.725-4.656-9.854-6.666-15.612-5.114-66.622 17.93-113.151 78.596-113.151 147.528 0 84.323 68.602 152.924 152.924 152.924 56.927 0 108.791-31.366 135.352-81.858 2.776-5.277 2.163-11.697-1.562-16.354-3.726-4.656-9.853-6.664-15.612-5.114zm-118.178 73.326c-67.78 0-122.924-55.144-122.924-122.924 0-44.253 23.869-84.269 60.772-105.922-3.018 12.074-4.57 24.51-4.57 36.961 0 84.322 68.602 152.923 152.924 152.923 1.191 0 2.386-.015 3.582-.045-22.917 24.588-55.187 39.007-89.784 39.007z"/><path
                         d="m318.096 295.712 38.904-11.849 38.902 11.85c1.442.439 2.913.652 4.369.652 4.621 0 9.086-2.141 11.97-5.96l24.509-32.445 38.422-13.301c5.938-2.056 9.965-7.595 10.09-13.878l.804-40.658 23.242-33.367c3.589-5.152 3.589-11.995 0-17.147l-23.242-33.365-.803-40.657c-.124-6.283-4.151-11.823-10.09-13.878l-38.422-13.302-24.507-32.447c-3.794-5.022-10.32-7.143-16.34-5.308l-38.904 11.85-38.901-11.85c-6.022-1.834-12.547.286-16.34 5.308l-24.509 32.445-38.422 13.301c-5.938 2.056-9.965 7.595-10.09 13.878l-.804 40.658-23.242 33.367c-3.589 5.152-3.589 11.995 0 17.147l23.242 33.364.803 40.658c.124 6.283 4.151 11.823 10.09 13.878l38.422 13.302 24.508 32.446c3.794 5.022 10.318 7.142 16.339 5.308zm-19.66-59.476c-1.793-2.374-4.251-4.161-7.062-5.134l-32.85-11.373-.686-34.747c-.059-2.964-.994-5.845-2.689-8.278l-19.868-28.522 19.869-28.524c1.695-2.433 2.63-5.313 2.689-8.277l.687-34.748 32.85-11.372c2.811-.973 5.27-2.76 7.062-5.134l20.943-27.725 33.249 10.128c2.85.868 5.893.868 8.742 0l33.25-10.128 20.943 27.726c1.793 2.374 4.251 4.161 7.062 5.134l32.85 11.373.686 34.747c.059 2.964.994 5.845 2.689 8.278l19.869 28.522-19.869 28.524c-1.695 2.433-2.63 5.313-2.689 8.277l-.687 34.747-32.85 11.372c-2.811.973-5.27 2.76-7.062 5.134l-20.943 27.725-33.249-10.128c-1.425-.434-2.898-.651-4.371-.651s-2.946.217-4.371.651l-33.25 10.127z"/><path
@@ -55,11 +55,11 @@
                         d="m44.394 186.606c2.928 2.93 6.767 4.394 10.606 4.394s7.678-1.464 10.606-4.394l40-40c5.858-5.858 5.858-15.355 0-21.213-5.857-5.858-15.355-5.858-21.213 0l-12.891 12.891c8.445-49.49 51.637-87.284 103.498-87.284h20c8.284 0 15-6.716 15-15s-6.716-15-15-15h-20c-69.254 0-126.484 52.42-134.124 119.663l-15.27-15.27c-5.857-5.858-15.355-5.858-21.213 0s-5.858 15.355 0 21.213z"/></g></svg>
                 <!--    <svg viewBox="0 0 511 511" xmlns="http://www.w3.org/2000/svg"><g><path d="m255.5 89.833c91.073 0 165.167 74.094 165.167 165.167 0 2.663-.064 5.36-.191 8.018l14.982.717c.139-2.895.209-5.833.209-8.734 0-99.345-80.822-180.167-180.167-180.167-3.35 0-6.743.094-10.084.278l.827 14.977c3.067-.17 6.181-.256 9.257-.256z"/><path d="m92.818 226.294-14.774-2.59c-.904 5.158-1.59 10.425-2.04 15.653l14.945 1.285c.412-4.793 1.041-9.621 1.869-14.348z"/><path d="m436.075 276.906c-28.556 25.473-57.172 47.064-96.667 51.645-42.819 4.966-86.3-10.222-116.768-40.69-30.427-30.427-45.733-73.985-40.69-116.768 4.661-39.539 26.137-68.074 51.644-96.667-29.849 7.86-58.331 16.2-83.757 34.634-33.202 24.071-57.656 59.376-68.322 98.99l14.484 3.9c13.235-49.155 48.545-89.192 94.639-108.888-39.226 61.424-30.046 144.023 21.412 195.39 51.47 51.379 133.906 60.692 195.409 21.399-31.223 73.255-113.344 114.388-190.719 95.707-73.205-17.674-126.407-85.264-126.407-160.558h-15c0 98.096 82.112 180.174 180.167 180.166 48.13-.004 95.065-19.761 128.755-54.114 28.941-29.511 41.562-65.19 51.82-104.146z"/><path d="m450.5 247.5h60v15h-60z"/><path d="m384.599 88.4h60v15.001h-60z" transform="matrix(.707 -.707 .707 .707 53.621 321.255)"/><path d="m407.099 382.5h15.001v60h-15.001z" transform="matrix(.707 -.707 .707 .707 -170.248 413.991)"/><path d="m248 0h15v60h-15z"/><path d="m248 451h15v60h-15z"/><path d="m61 435.501h-15v15h-15v15h15v15h15v-15h15v-15h-15z"/><path d="m91 75h15v-15h15v-15h-15v-15h-15v15h-15v15h15z"/><path d="m45.5 262.5v-15h-15v-15h-15v15h-15v15h15v15h15v-15z"/><path d="m75.333 405h15v15h-15z"/><path d="m31 90.402h15v15h-15z"/></g></svg>-->
             </span>
-            <span class="svg-icon-holder" id="btn-show-modal">
+            <span class="svg-icon-holder" id="btn-show-modal" title="Open help">
                 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path
                         d="M13.25 7c0 .69-.56 1.25-1.25 1.25s-1.25-.56-1.25-1.25.56-1.25 1.25-1.25 1.25.56 1.25 1.25zm10.75 5c0 6.627-5.373 12-12 12s-12-5.373-12-12 5.373-12 12-12 12 5.373 12 12zm-2 0c0-5.514-4.486-10-10-10s-10 4.486-10 10 4.486 10 10 10 10-4.486 10-10zm-13-2v2h2v6h2v-8h-4z"/></svg>
             </span>
-            <a class="svg-icon-holder" id="github-link" href="https://github.com/derlin/bitdowntoc" target="_blank">
+            <a class="svg-icon-holder" id="github-link" href="https://github.com/derlin/bitdowntoc" target="_blank" title="Go to code repository">
                 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24">
                     <path d="M12 2c5.514 0 10 4.486 10 10s-4.486 10-10 10-10-4.486-10-10 4.486-10 10-10zm0-2c-6.627 0-12 5.373-12 12s5.373 12 12 12 12-5.373 12-12-5.373-12-12-12zm0 6c-3.313 0-6 2.686-6 6 0 2.651 1.719 4.9 4.104 5.693.3.056.396-.13.396-.289v-1.117c-1.669.363-2.017-.707-2.017-.707-.272-.693-.666-.878-.666-.878-.544-.373.041-.365.041-.365.603.042.92.619.92.619.535.917 1.403.652 1.746.499.054-.388.209-.652.381-.802-1.333-.152-2.733-.667-2.733-2.965 0-.655.234-1.19.618-1.61-.062-.153-.268-.764.058-1.59 0 0 .504-.161 1.65.615.479-.133.992-.199 1.502-.202.51.002 1.023.069 1.503.202 1.146-.776 1.648-.615 1.648-.615.327.826.121 1.437.06 1.588.385.42.617.955.617 1.61 0 2.305-1.404 2.812-2.74 2.96.216.186.412.551.412 1.111v1.646c0 .16.096.347.4.288 2.383-.793 4.1-3.041 4.1-5.691 0-3.314-2.687-6-6-6z"/>
                 </svg>
@@ -75,8 +75,8 @@ <h1>Markdown TOC generator</h1>
     <div id="buttons-wrapper" class="flex-horizontal">
         <div id="select-profile">Preset:</div>
         <button id="btn-generate" class="fill">generate</button>
-        <button id="btn-copy">copy</button>
-        <button id="btn-toggle-options">options</button>
+        <button id="btn-copy" title="Copy the generated content to clipboard">copy</button>
+        <button id="btn-toggle-options" title="Tweak generation options (advanced)">options</button>
     </div>
 
     <div id="options-wrapper">
@@ -84,8 +84,8 @@ <h1>Markdown TOC generator</h1>
             <div class="content">
                 <div id="options"></div>
                 <div class="buttons" style="text-align: right;">
-                    <button id="btn-store-options" class="small secondary">Save</button>
-                    <button id="btn-reset-options" class="small secondary">Reset defaults</button>
+                    <button id="btn-store-options" class="small secondary" title="Save current options to local storage">Save</button>
+                    <button id="btn-reset-options" class="small secondary" title="Clear local storage">Reset defaults</button>
                 </div>
             </div>
         </div>