/* transition: property duration timing-function delay */

/* Single property transition */
.button {
  background: #3498db;
  transition: background 0.3s ease 0s;
  /* property, duration, timing, delay */
}

.button:hover {
  background: #2980b9;
}

/* Simplest form (duration only, rest defaults) */
.simple {
  transition: 0.3s;
  /* All properties, 0.3s duration, ease timing, 0 delay */
}

/* Property + duration (most common) */
.common {
  transition: background 0.3s;
  /* 0.3s, ease timing, 0 delay (defaults) */
}

/* All values specified */
.complete {
  transition: transform 0.5s cubic-bezier(0.4, 0.0, 0.2, 1) 0.1s;
  /* Property, duration, custom timing, delay */
}

/* Multiple properties (comma-separated) */
.multi {
  transition:
    background 0.3s ease,
    transform 0.5s ease,
    opacity 0.2s ease;
  /* Each property has its own timing */
}

/* Transition all properties */
.transition-all {
  transition: all 0.3s ease;
  /* Every property change gets the same timing */
}

/* Understanding the order */

/* Can omit property (defaults to 'all') */
.no-property {
  transition: 0.3s ease 0.1s;
  /* Same as: transition: all 0.3s ease 0.1s */
}

/* Can omit timing function (defaults to 'ease') */
.no-timing {
  transition: background 0.3s 0.1s;
  /* Same as: transition: background 0.3s ease 0.1s */
}

/* Can omit delay (defaults to '0s') */
.no-delay {
  transition: background 0.3s ease;
  /* Same as: transition: background 0.3s ease 0s */
}

/* Duration is the ONLY required value */
.minimal {
  transition: 0.3s;
  /* property=all, timing=ease, delay=0s */
}

/* Two values: property + duration (most common) */
.standard {
  transition: background 0.3s;
  /* timing=ease, delay=0s (defaults) */
}

/* Can't omit duration! */
.invalid {
  /* transition: background ease 0.1s; */
  /* ❌ ERROR: duration required, "ease" not recognized as duration */
}

/* Multiple properties with varying timings */
.different-timings {
  transition:
    background 0.2s ease,
    /* Fast color change */
    transform 0.5s cubic-bezier(0.4, 0, 0.2, 1),
    /* Slower transform with custom timing */
    opacity 0.3s ease 0.1s;
    /* Medium fade with delay */
}

/* Long-form (expanded) */
.long-form {
  transition-property: background, transform, box-shadow;
  transition-duration: 0.3s, 0.5s, 0.2s;
  transition-timing-function: ease, ease-out, cubic-bezier(0.4, 0, 0.2, 1);
  transition-delay: 0s, 0.1s, 0s;
}

/* Shorthand (equivalent) */
.shorthand {
  transition:
    background 0.3s ease 0s,
    transform 0.5s ease-out 0.1s,
    box-shadow 0.2s cubic-bezier(0.4, 0, 0.2, 1) 0s;
}

/* Both do the same thing, shorthand is more concise */

/* Shorthand 'all' keyword */
.all-shorthand {
  transition: all 0.3s ease 0.1s;
}

/* Equivalent long-form */
.all-longform {
  transition-property: all;
  transition-duration: 0.3s;
  transition-timing-function: ease;
  transition-delay: 0.1s;
}

/* Mix of shorthand and long-form (avoid - confusing) */
.mixed {
  transition: all 0.3s;
  /* 3 different styles, don't mix if possible */
  transition-delay: 0.1s;
}

/* Button with multiple transitions */
.button {
  background: #3498db;
  transform: scale(1);
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  transition:
    background 0.2s ease,
    transform 0.3s ease,
    box-shadow 0.3s ease;
}

.button:hover {
  background: #2980b9;
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

/* Card with staggered entrance */
.card {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.4s ease, transform 0.4s ease 0.1s;
  /* Opacity fades immediately, transform slides after 0.1s */
}

.card.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Sidebar slide animation */
.sidebar {
  transform: translateX(-100%);
  opacity: 0;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease;
}

.sidebar.open {
  transform: translateX(0);
  opacity: 1;
}

/* Smooth theme switch */
body {
  background-color: #ffffff;
  color: #000000;
  transition: background-color 0.3s ease, color 0.3s ease;
}

body.dark-mode {
  background-color: #1a1a1a;
  color: #ffffff;
}

/* Navigation underline effect */
.nav-link {
  position: relative;
  color: #333;
  transition: color 0.3s ease;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: #3498db;
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-link:hover {
  color: #3498db;
}

.nav-link:hover::after {
  width: 100%;
}

/* Dropdown with multiple stages */
.dropdown-menu {
  max-height: 0;
  opacity: 0;
  pointer-events: none;
  overflow: hidden;
  transition: max-height 0.3s ease, opacity 0.2s ease;
}

.dropdown-trigger:hover ~ .dropdown-menu {
  max-height: 400px;
  opacity: 1;
  pointer-events: auto;
}

/* Define standard transitions as custom properties */
:root {
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
  --transition-smooth: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Apply consistently across components */
.button {
  transition: background var(--transition-base), transform var(--transition-base);
}

.card {
  transition: transform var(--transition-smooth), box-shadow var(--transition-base);
}

.modal {
  transition: opacity var(--transition-slow), transform var(--transition-smooth);
}

/* Easily switch all transitions for different themes */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0.01s ease;
    --transition-base: 0.01s ease;
    --transition-slow: 0.01s ease;
    --transition-smooth: 0.01s ease;
  }
}

/* Define transition by purpose */
:root {
  --transition-micro: 0.15s ease;
  /* Quick feedback (0.1-0.2s) */
  --transition-standard: 0.3s ease;
  /* Normal interaction (0.2-0.4s) */
  --transition-transition: 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  /* Page/modal transitions (0.4-0.8s) */
  --transition-subtle: 1s ease;
  /* Background animations (0.8s+) */
}

.interactive {
  transition: all var(--transition-micro);
}

.content-change {
  transition: all var(--transition-standard);
}

.page-transition {
  transition: all var(--transition-transition);
}

/* ❌ MISTAKE: Duration in wrong position */
.wrong {
  /* transition: ease 0.3s background; */
  /* ❌ Error: "ease" is not a duration */
}

/* ✓ CORRECT: Duration always second */
.correct {
  transition: background 0.3s ease;
}

/* ❌ MISTAKE: Using "all" everywhere */
.bad-all {
  transition: all 0.3s;
  /* Transitions every property, can be inefficient */
}

/* ✓ BETTER: Specify needed properties */
.good-specific {
  transition: background 0.3s, transform 0.3s;
  /* Only transitions what needs it */
}

/* ❌ MISTAKE: Overly complex timing */
.overcomplicated {
  transition:
    background 0.15s cubic-bezier(0.1, 0.2, 0.3, 0.4),
    border 0.2s cubic-bezier(0.5, 0.6, 0.7, 0.8),
    box-shadow 0.25s cubic-bezier(0.1, 0.8, 0.2, 0.9);
}

/* ✓ BETTER: Consistent, simple timing */
.simple-timing {
  transition:
    background 0.3s ease,
    border 0.3s ease,
    box-shadow 0.3s ease;
}

/* ❌ MISTAKE: Conflicting transitions */
.conflicting {
  transition: all 0.3s;
  transition: background 0.5s; /* Overwrites first line */
}

/* ✓ CORRECT: Single transition declaration */
.proper {
  transition: all 0.3s;
}

/* Best practice: Document transition purposes */
.button-hover {
  /* Quick color feedback for user action */
  transition: background 0.2s ease;
}

.modal-entrance {
  /* Smooth fade-in of modal dialog */
  transition: opacity 0.3s ease, transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.content-reveal {
  /* Staggered reveal of content */
  transition: opacity 0.4s ease, transform 0.4s ease 0.1s;
}