diff --git a/index.html b/index.html
index 73266b6..9014d74 100644
--- a/index.html
+++ b/index.html
@@ -73,21 +73,21 @@
 			<div class="tools">
 				<div>
 					Marcdown
-					<button onclick="apply('bold')">B</button>
-					<button onclick="apply('italic')"><i>I</i></button>
-					<button onclick="apply('strike')"><strike>S</strike></button>
-					<button onclick="apply('h1')">H1</button>
-					<button onclick="apply('h2')">H2</button>
-					<button onclick="apply('h3')">H3</button>
-					<button onclick="apply('ul')">●</button>
-					<button onclick="apply('ol')">1.</button>
-					<button onclick="apply('bq')">””</button>
-					<button onclick="apply('code')">&lt;></button>
-					<button onclick="apply('link')">A</button>
-					<button onclick="apply('check')">✔</button>
-					<button onclick="apply('image')">i</button>
-					<button onclick="apply('hr')">——</button>
-					<button onclick="apply('table')">⚏</button>
+					<button onclick="apply('bold')" title="Bold">B</button>
+					<button onclick="apply('italic')" title="Italic"><i>I</i></button>
+					<button onclick="apply('strike')" title="Strikethrough"><strike>S</strike></button>
+					<button onclick="apply('h1')" title="Header 1">H1</button>
+					<button onclick="apply('h2')" title="Header 2">H2</button>
+					<button onclick="apply('h3')" title="Header 3">H3</button>
+					<button onclick="apply('ul')" title="Unordered list">●</button>
+					<button onclick="apply('ol')" title="Ordered list">1.</button>
+					<button onclick="apply('check')" title="Check list">✔</button>
+					<button onclick="apply('bq')" title="Blockquote">””</button>
+					<button onclick="apply('code')" title="Code">&lt;></button>
+					<button onclick="apply('link')" title="Link">A</button>
+					<button onclick="apply('image')" title="Image">i</button>
+					<button onclick="apply('hr')" title="Horizontal rule">——</button>
+					<button onclick="apply('table')" title="Table">⚏</button>
 				</div>
 				<div>
 					<span>
@@ -98,7 +98,7 @@
 					</span>
 					<button type="button" onclick="download();" id="save" disabled>Save</button>
 					🌙
-					<label class="theme-switch" for="checkbox">
+					<label class="theme-switch" for="checkbox" title="Night mode">
 						<input type="checkbox" id="checkbox">
 						<div class="slider round"></div>
 					</label>
@@ -118,9 +118,9 @@
 					<span id="colno"></span>
 				</div>
 				<div>
-					<button onclick="preview('nill')">←</button>
-					<button onclick="preview('half')">●</button>
-					<button onclick="preview('full')">→</button>
+					<button onclick="preview('nill')" title="Hide editor">←</button>
+					<button onclick="preview('half')" title="Side by side">●</button>
+					<button onclick="preview('full')" title="Hide viewer">→</button>
 				</div>
 				<div style="flex: 1 1 0; text-align: right;">
 					<span id="charcount"></span>