Responsive Design

Mobile-First Approach

Phương pháp thiết kế mobile-first bắt đầu từ mobile và mở rộng lên desktop.

Media Queries

Breakpoints cơ bản

/* Mobile First */
.container {
  padding: 1rem;
}

/* Tablet */
@media (min-width: 768px) {
  .container {
    padding: 2rem;
  }
}

/* Desktop */
@media (min-width: 1024px) {
  .container {
    padding: 3rem;
  }
}

Common Breakpoints

/* Small devices (landscape phones, 576px and up) */
@media (min-width: 576px) { }

/* Medium devices (tablets, 768px and up) */
@media (min-width: 768px) { }

/* Large devices (desktops, 992px and up) */
@media (min-width: 992px) { }

/* Extra large devices (large desktops, 1200px and up) */
@media (min-width: 1200px) { }

Responsive Units

Relative Units

.container {
  width: 100%; /* Percentage */
  padding: 1rem; /* Root EM */
  font-size: 1.125rem; /* Relative to root */
  margin: 2em; /* Relative to parent */
  width: 50vw; /* Viewport Width */
  height: 100vh; /* Viewport Height */
}

Fluid Typography

html {
  font-size: 16px;
}

@media (min-width: 768px) {
  html {
    font-size: 18px;
  }
}

@media (min-width: 1200px) {
  html {
    font-size: 20px;
  }
}

h1 {
  font-size: clamp(2rem, 5vw, 4rem);
}

Responsive Images

srcset và sizes

<img 
  srcset="image-320w.jpg 320w,
          image-480w.jpg 480w,
          image-800w.jpg 800w"
  sizes="(max-width: 320px) 280px,
         (max-width: 480px) 440px,
         800px"
  src="image-800w.jpg" 
  alt="Responsive image">

picture element

<picture>
  <source media="(min-width: 1200px)" srcset="large.jpg">
  <source media="(min-width: 768px)" srcset="medium.jpg">
  <img src="small.jpg" alt="Responsive image">
</picture>

Responsive Navigation

Hamburger Menu

<nav class="navbar">
  <div class="nav-brand">Logo</div>
  <button class="nav-toggle">☰</button>
  <ul class="nav-menu">
    <li><a href="#">Home</a></li>
    <li><a href="#">About</a></li>
    <li><a href="#">Services</a></li>
    <li><a href="#">Contact</a></li>
  </ul>
</nav>

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }
  
  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: 1rem;
  }
  
  .nav-menu.active {
    display: flex;
  }
}