CSS Basics

CSS (Cascading Style Sheets) is used to style and layout web pages.

Selectors

/* Element selector */
h1 {
    color: blue;
}

/* Class selector */
.highlight {
    background-color: yellow;
}

/* ID selector */
#header {
    font-size: 24px;
}

/* Attribute selector */
input[type="text"] {
    border: 1px solid #ccc;
}

Box Model

.box {
    width: 200px;
    height: 100px;
    padding: 20px;
    border: 2px solid black;
    margin: 10px;
}

Flexbox

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
}

.item {
    flex: 1;
}

Grid

.grid-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

Responsive Design

/* Mobile first */
.container {
    width: 100%;
}

/* Tablet */
@media (min-width: 768px) {
    .container {
        width: 750px;
    }
}

/* Desktop */
@media (min-width: 1024px) {
    .container {
        width: 1000px;
    }
}

CSS is essential for creating beautiful and responsive web interfaces!