# Referensi Cepat CSS

*Selector, layout, flexbox, grid, animasi, desain responsif*

> Source: MDN Web Docs (developer.mozilla.org) · MIT

## Selector

### Selector Dasar

| Command | Description |
|---------|-------------|
| `*` | Universal — semua elemen |
| `div` | Tipe — semua elemen `<div>` |
| `.class` | Class — elemen dengan class |
| `#id` | ID — elemen dengan id |
| `[attr]` | Atribut — memiliki atribut |
| `[attr="val"]` | Atribut sama dengan nilai |

### Kombinator

| Command | Description |
|---------|-------------|
| `A B` | Keturunan (kedalaman berapa pun) |
| `A > B` | Anak langsung saja |
| `A + B` | Sibling bersebelahan (berikutnya) |
| `A ~ B` | Sibling umum (semua setelahnya) |

### Pseudo-class

| Command | Description |
|---------|-------------|
| `:hover` | Mouse di atas elemen |
| `:focus` | Elemen mendapat fokus |
| `:first-child` | Anak pertama dari parent |
| `:nth-child(n)` | Anak ke-n (1-based, `odd`, `even`, `2n+1`) |
| `:not(sel)` | Negasi — kecualikan yang cocok |
| `:has(sel)` | Selector parent (mengandung yang cocok) |

### Pseudo-element

| Command | Description |
|---------|-------------|
| `::before` | Sisipkan konten sebelum elemen |
| `::after` | Sisipkan konten setelah elemen |
| `::placeholder` | Gaya teks placeholder input |
| `::selection` | Gaya teks yang disorot |

## Box Model

### Box Sizing

```
/* Include padding/border in width */
*, *::before, *::after {
  box-sizing: border-box;
}
```

### Properti

| Command | Description |
|---------|-------------|
| `margin` | Ruang di luar border |
| `border` | Tepi di sekitar padding |
| `padding` | Ruang di dalam border |
| `width / height` | Dimensi konten |
| `outline` | Ring di luar margin (tanpa ruang) |

### Shorthand

```
margin: 10px;           /* all sides */
margin: 10px 20px;      /* vertical | horizontal */
margin: 10px 20px 30px; /* top | horiz | bottom */
margin: 10px 20px 30px 40px; /* T R B L */
```

## Flexbox

### Container

```
.flex {
  display: flex;
  justify-content: center; /* main axis */
  align-items: center;     /* cross axis */
  gap: 1rem;
}
```

### Properti Container

| Command | Description |
|---------|-------------|
| `flex-direction` | `row` \| `column` \| `row-reverse` \| `column-reverse` |
| `flex-wrap` | `nowrap` \| `wrap` \| `wrap-reverse` |
| `justify-content` | `flex-start` \| `center` \| `space-between` \| `space-around` \| `space-evenly` |
| `align-items` | `stretch` \| `center` \| `flex-start` \| `flex-end` \| `baseline` |
| `align-content` | Perataan sumbu silang multi-baris |
| `gap` | Jarak antar item flex |

### Properti Item

| Command | Description |
|---------|-------------|
| `flex: 1` | Tumbuh mengisi ruang yang tersedia |
| `flex: 0 0 200px` | Lebar tetap, tidak tumbuh/menyusut |
| `align-self` | Override align-items untuk satu item |
| `order` | Ubah urutan visual (default 0) |

## Grid

### Container

```
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: auto 1fr auto;
  gap: 1rem;
}
```

### Properti Container

| Command | Description |
|---------|-------------|
| `grid-template-columns` | Definisikan kolom: `1fr 2fr`, `repeat(3, 1fr)` |
| `grid-template-rows` | Definisikan baris |
| `grid-template-areas` | Area bernama: `"header header" "nav main"` |
| `gap` | Jarak antar baris dan kolom |
| `justify-items` | Perataan item horizontal |
| `align-items` | Perataan item vertikal |

### Penempatan Item

```
.item {
  grid-column: 1 / 3;   /* span cols 1-2 */
  grid-row: 1 / -1;     /* span all rows */
  grid-area: header;    /* named area */
}
```

## Tipografi

### Properti Font

| Command | Description |
|---------|-------------|
| `font-family` | Stack typeface: `'Inter', sans-serif` |
| `font-size` | Ukuran: `1rem`, `16px`, `clamp(1rem, 2vw, 2rem)` |
| `font-weight` | `normal` (400) \| `bold` (700) \| `100`-`900` |
| `font-style` | `normal` \| `italic` \| `oblique` |
| `line-height` | Spasi baris: `1.5` (tanpa satuan direkomendasikan) |
| `letter-spacing` | Spasi karakter: `0.05em` |

### Properti Teks

| Command | Description |
|---------|-------------|
| `text-align` | `left` \| `center` \| `right` \| `justify` |
| `text-decoration` | `none` \| `underline` \| `line-through` |
| `text-transform` | `uppercase` \| `lowercase` \| `capitalize` |
| `text-overflow` | `ellipsis` (dengan overflow: hidden) |
| `white-space` | `nowrap` \| `pre` \| `pre-wrap` |
| `word-break` | `break-all` \| `break-word` |

## Warna & Background

### Format Warna

```
color: #ff6600;             /* hex */
color: rgb(255, 102, 0);    /* rgb */
color: hsl(24, 100%, 50%);  /* hsl */
color: oklch(70% 0.15 50);  /* oklch */
```

### Properti Background

| Command | Description |
|---------|-------------|
| `background-color` | Warna solid: `#f0f0f0` |
| `background-image` | `url(img.jpg)` atau gradient |
| `background-size` | `cover` \| `contain` \| `100px 200px` |
| `background-position` | `center` \| `top right` \| `50% 50%` |
| `background-repeat` | `no-repeat` \| `repeat-x` \| `repeat-y` |

### Gradient

```
background: linear-gradient(to right, #f00, #00f);
background: radial-gradient(circle, #fff, #000);
background: conic-gradient(red, yellow, green);
```

## Transisi & Animasi

### Transisi

```
.btn {
  transition: background 0.3s ease, transform 0.2s;
}
.btn:hover {
  background: #0056b3;
  transform: scale(1.05);
}
```

### Properti Transisi

| Command | Description |
|---------|-------------|
| `transition-property` | Properti mana yang dianimasikan |
| `transition-duration` | Durasi: `0.3s`, `300ms` |
| `transition-timing-function` | `ease` \| `linear` \| `ease-in-out` \| `cubic-bezier()` |
| `transition-delay` | Tunggu sebelum mulai |

### Animasi Keyframe

```
@keyframes spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}
.icon { animation: spin 1s linear infinite; }
```

### Properti Animasi

| Command | Description |
|---------|-------------|
| `animation-name` | Referensi nama @keyframes |
| `animation-duration` | Durasi satu siklus |
| `animation-iteration-count` | `1` \| `3` \| `infinite` |
| `animation-direction` | `normal` \| `alternate` \| `reverse` |
| `animation-fill-mode` | `forwards` \| `backwards` \| `both` |

## Desain Responsif

### Media Query

```
@media (max-width: 768px) {
  .sidebar { display: none; }
}
@media (prefers-color-scheme: dark) {
  body { background: #1a1a1a; color: #eee; }
}
```

### Breakpoint Umum

| Command | Description |
|---------|-------------|
| `max-width: 480px` | Ponsel |
| `max-width: 768px` | Tablet |
| `max-width: 1024px` | Laptop kecil |
| `max-width: 1280px` | Desktop |

### Satuan Viewport

| Command | Description |
|---------|-------------|
| `vw / vh` | % lebar / tinggi viewport |
| `dvh` | Tinggi viewport dinamis (aman untuk mobile) |
| `svh / lvh` | Tinggi viewport kecil / besar |
| `cqi` | Ukuran inline container query |

### Container Query

```
.card-wrapper { container-type: inline-size; }
@container (min-width: 400px) {
  .card { flex-direction: row; }
}
```

## Positioning

### Nilai Position

| Command | Description |
|---------|-------------|
| `static` | Default — alur dokumen normal |
| `relative` | Offset dari posisi normal; tetap mengisi ruang |
| `absolute` | Relatif terhadap ancestor yang ter-position |
| `fixed` | Relatif terhadap viewport; tetap saat scroll |
| `sticky` | Berganti relative/fixed berdasarkan scroll |

### Pola Centering

```
/* Flex center */
display: flex;
justify-content: center;
align-items: center;

/* Grid center */
display: grid;
place-items: center;
```

### Stacking

| Command | Description |
|---------|-------------|
| `z-index` | Urutan tumpukan (lebih tinggi = di atas); butuh `position` |
| `isolation: isolate` | Membuat stacking context baru |

## Custom Properties

### Definisi & Penggunaan

```
:root {
  --color-primary: #3b82f6;
  --spacing-md: 1rem;
}
.btn {
  background: var(--color-primary);
  padding: var(--spacing-md);
}
```

### Nilai Fallback

```
color: var(--accent, #ff6600);
/* uses #ff6600 if --accent is not defined */
```

### Theming Dinamis

```
[data-theme="dark"] {
  --bg: #1a1a2e;
  --text: #e0e0e0;
}
body { background: var(--bg); color: var(--text); }
```