diff --git a/style.css b/style.css
new file mode 100644
index 0000000..f09b6b8
--- /dev/null
+++ b/style.css
@@ -0,0 +1,135 @@
+* {
+    margin: 0;
+    padding: 0;
+    box-sizing: border-box;
+}
+
+body {
+    font-family: Arial, sans-serif;
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    min-height: 100vh;
+    background-color: #f9f9f9;
+    transition: background-color 0.3s, color 0.3s;
+    padding: 20px;
+}
+
+.youtube-calculadora {
+    width: 100%;
+    max-width: 500px;
+    min-width: 280px;
+    background: #fff;
+    padding: 20px;
+    border-radius: 8px;
+    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
+    text-align: center;
+    transition: background-color 0.3s, color 0.3s;
+}
+
+h1 {
+    color: #ff0000;
+}
+
+.form label {
+    display: block;
+    margin-top: 10px;
+    text-align: left;
+}
+
+input[type="number"] {
+    width: 100%;
+    padding: 10px;
+    margin-top: 5px;
+    margin-bottom: 15px;
+    border: 1px solid #ddd;
+    border-radius: 4px;
+    font-size: 1em;
+}
+
+button {
+    padding: 12px;
+    width: 100%;
+    border: none;
+    border-radius: 4px;
+    cursor: pointer;
+    font-size: 1em;
+    margin-top: 10px;
+}
+
+button.theme-toggle {
+    background-color: #444;
+    color: #fff;
+    margin-bottom: 10px;
+}
+
+button.theme-toggle:hover {
+    background-color: #333;
+}
+
+button.calculate {
+    background-color: #ff0000;
+    color: #fff;
+}
+
+button.calculate:hover {
+    background-color: #e60000;
+}
+
+.result {
+    margin-top: 20px;
+}
+
+.result h2 {
+    font-size: 1.2em;
+    color: #333;
+}
+
+.result p {
+    font-size: 1.5em;
+    font-weight: bold;
+    color: #000;
+}
+
+body.dark {
+    background-color: #121212;
+    color: #e0e0e0;
+}
+
+.youtube-calculadora.dark {
+    background-color: #333;
+    color: #e0e0e0;
+}
+
+.youtube-calculadora.dark button.theme-toggle {
+    background-color: #ff0000;
+}
+
+.youtube-calculadora.dark button.theme-toggle:hover {
+    background-color: #e60000;
+}
+
+.youtube-calculadora.dark input[type="number"] {
+    background-color: #444;
+    color: #e0e0e0;
+    border: 1px solid #666;
+}
+
+.youtube-calculadora.dark .result p {
+    color: #fff;
+}
+
+@media (min-width: 768px) {
+    .youtube-calculadora {
+        padding: 30px;
+    }
+    
+    input[type="number"] {
+        font-size: 1.1em;
+        padding: 12px;
+    }
+
+    button {
+        font-size: 1.1em;
+    }
+}