“`html

body {
font-family: Arial, Helvetica, sans-serif;
}

h1,
h2,
h3,
h4,
h5,
h6 {
font-weight: bold;
}

h1 {
font-size: 2.5em;
}

h2 {
font-size: 2em;
}

h3 {
font-size: 1.5em;
}

h4 {
font-size: 1.2em;
}

h5 {
font-size: 1em;
}

h6 {
font-size: 0.8em;
}

p {
font-size: 1em;
}

a {
color: #000;
text-decoration: none;
}

a:hover {
color: #000;
text-decoration: underline;
}

.container {
max-width: 1200px;
padding: 0 15px;
}

.row {
display: flex;
flex-wrap: wrap;
}

.col-12,
.col-6 {
flex: 0 0 100%;
max-width: 100%;
}

.col-9 {
flex: 0 0 75%;
max-width: 75%;
}

.col-3 {
flex: 0 0 25%;
max-width: 25%;
}

.main {
flex: 0 0 75%;
max-width: 75%;
}

.sidebar {
flex: 0 0 25%;
max-width: 25%;
}

.image-container {
width: 100%;
padding: 15px;
background-color: #f5f5f5;
}

.image {
width: 100%;
}

.product-info {
padding: 15px;
background-color: #fff;
}

.product-name {
font-size: 1.5em;
}

.product-description {
font-size: 1em;
}

.product-features {
list-style-type: none;
padding: 0;
}

.product-features li {
font-size: 1em;
padding: 5px 0;
}

.product-price {
font-size: 1.2em;
}

.product-warranty {
font-size: 1em;
color: #000;
}

.product-availability {
font-size: 1em;
color: #000;
}

.product-call-to-action {
padding: 15px;
background-color: #000;
color: #fff;
}

.product-call-to-action a {
color: #fff;
text-decoration: none;
}

.product-call-to-action a:hover {
color: #fff;
text-decoration: underline;
}

.catalog-link {
font-size: 1em;
color: #000;
}

.catalog-link:hover {
color: #000;
text-decoration: underline;
}

.warning {
color: #ff0000;
}