diff --git a/src/main/index.html b/src/main/index.html
index 930e055..54fbb2c 100644
--- a/src/main/index.html
+++ b/src/main/index.html
@@ -5,7 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="author" content="Florine W. Dekker" />
     <meta name="application-name" content="Converter" />
-    <meta name="description" content="Convert numbers to and from various bases." />
+    <meta name="description" content="Convert instantly between binary, decimal, hexadecimal, base64, and ASCII." />
     <meta name="theme-color" content="#0033cc" />
 
     <meta name="fwd:auto:show-main" />
@@ -43,7 +43,7 @@
                     <h1><a href=".">Converter</a></h1>
                     <h2>
                         Convert numbers to and from various bases.
-                        Separate values by commas to convert multiple at the same time.
+                        Use commas to separate multiple values.
                     </h2>
                 </hgroup>
             </header>
diff --git a/src/main/js/main.js b/src/main/js/main.js
index 8620b41..01eb5cb 100644
--- a/src/main/js/main.js
+++ b/src/main/js/main.js
@@ -139,15 +139,28 @@ class NumeralSystemInput {
         const label = stringToHtml(`<label for="b${base}-input">${this.name} <small>(base ${base})</small></label>`);
         this.wrapper.appendChild(label);
 
-        this.textarea = stringToHtml(`<textarea id="b${base}-input" class="number-input"></textarea>`);
+        this.textarea = stringToHtml(`<textarea id="b${base}-input" class="number-input" rows="4"></textarea>`);
         this.textarea.addEventListener("beforeinput", event => {
-            if (!this.numeralSystem.isLegal(event.data))
+            if (
+                (
+                    event.data == null && event.inputType === "insertLineBreak" &&
+                    !this.numeralSystem.alphabet.includes("\n")
+                ) ||
+                (
+                    event.data != null && !this.numeralSystem.isLegal(event.data)
+                )
+            ) {
                 event.preventDefault();
+            }
         });
         this.textarea.addEventListener("input", () => {
-            if (this.textarea.value === "") return;
+            clearInputValidity(this.textarea);
 
-            updateAllInputs(this, this.numeralSystem.basesToDecimals(this.getValues()));
+            try {
+                updateAllInputs(this, this.numeralSystem.basesToDecimals(this.getValues()));
+            } catch (error) {
+                showInputInvalid(this.textarea, error.message);
+            }
         });
         this.wrapper.appendChild(this.textarea);
 
@@ -180,6 +193,7 @@ class NumeralSystemInput {
      * @param decimalNumbers {bigInt[]} the decimal numbers to represent in the input
      */
     setValues(decimalNumbers) {
+        clearInputValidity(this.textarea);
         this.textarea.value = this.numeralSystem.decimalsToBases(decimalNumbers).join(",");
     }
 }
@@ -234,12 +248,14 @@ class Base64NumeralSystem extends NumeralSystem {
      * @returns {bigInt} the decimal representation of `baseString`
      */
     baseToDecimal(baseString) {
-        if (baseString.length % 4 === 1) throw new Error("Invalid input string length.");
-
-        const normalBaseString = stringReplaceAlls(baseString, this.alphabet, Base64NumeralSystem.defaultAlphabet());
-        const hex = Array.from(atob(normalBaseString))
-            .map(char => char.charCodeAt(0).toString(16).padStart(2, "0")).join("");
-        return bigInt(hex, 16);
+        try {
+            const normalBaseString = stringReplaceAlls(baseString, this.alphabet, Base64NumeralSystem.defaultAlphabet());
+            const hex = Array.from(atob(normalBaseString))
+                .map(char => char.charCodeAt(0).toString(16).padStart(2, "0")).join("");
+            return bigInt(hex, 16);
+        } catch (error) {
+            throw new Error("Invalid base64 string. Maybe the padding is wrong?");
+        }
     }
 }
 
@@ -316,7 +332,6 @@ class NumeralSystemInputWithToggleableSeparator extends NumeralSystemInput {
             console.warn("Toggleable separator input incorrectly used on numeral system without comma in alphabet.");
 
         super(name, numeralSystem);
-        this.textarea.addEventListener("input", () => clearInputValidity(this.textarea));
 
         const id = `b${this.numeralSystem.base}-separator-toggle`;
         const checkboxContainer = document.createElement("div");