CSS Styling Skill

Instructions

When writing CSS:

1. Modern CSS Reset

*, *::before, *::after {
  box-sizing: border-box;
}

* {
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
}

body {
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
}

input, button, textarea, select {
  font: inherit;
}

p, h1, h2, h3, h4, h5, h6 {
  overflow-wrap: break-word;
}

2. CSS Custom Properties (Variables)

:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-secondary: #64748b;
  --color-success: #22c55e;
  --color-error: #ef4444;

  /* Typography */
  --font-sans: system-ui, -apple-system, sans-serif;
  --font-mono: ui-monospace, monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-12: 3rem;
  --space-16: 4rem;

  /* Borders */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f172a;
    --color-text: #f1f5f9;
  }
}

3. Flexbox Layouts

/* Center anything */
.center {
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Space between */
.space-between {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Stack vertically */
.stack {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

/* Wrap items */
.flex-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

4. Grid Layouts

/* Auto-fit responsive grid */
.grid-auto {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-6);
}

/* Fixed columns */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}

/* Sidebar layout */
.with-sidebar {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: var(--space-8);
}

/* Holy grail layout */
.holy-grail {
  display: grid;
  grid-template:
    "header header header" auto
    "nav main aside" 1fr
    "footer footer footer" auto
    / 200px 1fr 200px;
  min-height: 100vh;
}

5. Responsive Design

/* Mobile-first breakpoints */
/* Base: Mobile */

@media (min-width: 640px) {
  /* Tablet */
}

@media (min-width: 1024px) {
  /* Desktop */
}

@media (min-width: 1280px) {
  /* Large desktop */
}

/* Container queries */
.card-container {
  container-type: inline-size;
}

@container (min-width: 400px) {
  .card {
    display: flex;
  }
}

/* Clamp for fluid typography */
h1 {
  font-size: clamp(2rem, 5vw, 4rem);
}

6. Common Components

Buttons:

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-weight: 500;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-primary {
  background: var(--color-primary);
  color: white;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

Cards:

.card {
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.card-body {
  padding: var(--space-6);
}

.card-title {
  font-size: var(--text-xl);
  font-weight: 600;
  margin-bottom: var(--space-2);
}

Forms:

.input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 1px solid #e2e8f0;
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  transition: border-color var(--transition-fast);
}

.input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.input:invalid {
  border-color: var(--color-error);
}

7. Animations

/* Fade in */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.fade-in {
  animation: fadeIn var(--transition-normal) ease-out;
}

/* Slide up */
@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.slide-up {
  animation: slideUp var(--transition-normal) ease-out;
}

/* Respect user preferences */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;

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