:root {
  --motion-expo: cubic-bezier(.16, 1, .3, 1);
  --motion-swift: cubic-bezier(.2, .8, .2, 1);
}

@keyframes motion-typeset-in {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes motion-chain-word-in {
  0% { opacity: 0; transform: translateY(10px); }
  62% { opacity: 1; transform: translateY(0); }
  100% { opacity: 1; transform: translateY(0); }
}

@keyframes motion-chain-rule {
  0% { opacity: 0; transform: scaleX(0); }
  45%, 76% { opacity: .65; transform: scaleX(1); }
  100% { opacity: 0; transform: scaleX(1); }
}

@keyframes motion-arrow-in {
  from { opacity: 0; transform: translateX(-6px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes motion-target-start {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes motion-stat-flip {
  0% { opacity: .3; transform: translateY(-5px); }
  100% { opacity: 1; transform: translateY(0); }
}

@keyframes motion-message-in {
  from { opacity: 0; transform: translateX(-7px); clip-path: inset(0 100% 0 0); }
  to { opacity: 1; transform: translateX(0); clip-path: inset(0 0 0 0); }
}

@keyframes motion-panel-open {
  from { opacity: 0; transform: translateY(-6px); clip-path: inset(0 0 100% 0); }
  to { opacity: 1; transform: translateY(0); clip-path: inset(0 0 0 0); }
}

@keyframes motion-popover-open {
  from { opacity: 0; transform: translateY(8px) scale(.985); box-shadow: 3px 4px 0 rgba(18, 18, 17, 0.08); }
  to { opacity: 1; transform: translateY(0) scale(1); box-shadow: 10px 12px 0 rgba(18, 18, 17, 0.16); }
}

@keyframes motion-scrim-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes motion-result-in {
  from { opacity: 0; transform: translateY(14px) scale(.99); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

/* Coordinated first impression: the page settles like a freshly composed proof. */
.entry-section { animation: motion-typeset-in 620ms 560ms var(--motion-expo) both; }
.margin-column .stats-bar { animation: motion-typeset-in 560ms 620ms var(--motion-expo) both; }
.margin-column .side-actions { animation: motion-typeset-in 560ms 690ms var(--motion-expo) both; }
.margin-column .note-block:nth-of-type(1) { animation: motion-typeset-in 560ms 750ms var(--motion-expo) both; }
.margin-column .note-block:nth-of-type(2) { animation: motion-typeset-in 560ms 810ms var(--motion-expo) both; }

.game-mode-btn,
.diff-btn,
.level-card,
.hint-word,
.campaign-reset,
.campaign-hud button {
  transition:
    color 180ms ease,
    background-color 180ms ease,
    border-color 180ms ease,
    box-shadow 220ms var(--motion-expo),
    transform 220ms var(--motion-expo),
    opacity 180ms ease;
}

.game-mode-btn:hover:not(:disabled),
.campaign-reset:hover:not(:disabled),
.campaign-hud button:hover:not(:disabled) {
  color: var(--head);
}

.game-mode-btn:active:not(:disabled),
.diff-btn:active:not(:disabled),
.campaign-reset:active:not(:disabled),
.campaign-hud button:active:not(:disabled) {
  transform: translateY(1px);
}

.btn:not(:disabled):hover { transform: translateY(-1px); }
.btn-primary:not(:disabled):hover { box-shadow: 6px 6px 0 var(--rule); }
.btn-primary:not(:disabled):active { transform: translate(3px, 3px); box-shadow: 1px 1px 0 var(--rule); }

.hint-word:hover:not(:disabled) { transform: translateY(-2px); }

.level-card:hover:not(:disabled) {
  z-index: 1;
  transform: translateY(-3px);
  box-shadow: 0 8px 0 rgb(23 23 21 / .08);
}

.level-card:active:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 3px 0 rgb(23 23 21 / .1);
}

.input-area input {
  transition: border-color 180ms ease, background-color 180ms ease, box-shadow 220ms var(--motion-expo);
}

.input-area input:focus {
  box-shadow: inset 0 -2px 0 var(--head), 4px 4px 0 rgb(35 91 154 / .1);
  outline: none;
}

.chain-word.motion-chain-enter {
  position: relative;
  animation: motion-chain-word-in 460ms var(--motion-expo) both;
}

.chain-word.motion-chain-enter::after {
  position: absolute;
  right: 0;
  bottom: -3px;
  left: 0;
  height: 1px;
  content: "";
  background: currentColor;
  transform-origin: left center;
  animation: motion-chain-rule 520ms 40ms var(--motion-expo) both;
}

.chain-arrow.motion-chain-enter {
  animation: motion-arrow-in 300ms var(--motion-expo) both;
}

.target-letters.motion-target-refresh {
  animation: motion-target-start 420ms var(--motion-expo) both;
}

.stat .value.motion-stat-change,
.campaign-move-count strong.motion-stat-change,
.campaign-progress-value.motion-stat-change {
  animation: motion-stat-flip 340ms var(--motion-expo) both;
}

.message.show.motion-message-enter { animation: motion-message-in 340ms var(--motion-expo) both; }
.hints-panel.show { animation: motion-panel-open 320ms var(--motion-expo) both; }
.solve-panel.motion-panel-enter { animation: motion-panel-open 340ms var(--motion-expo) both; }

.campaign-home:not([hidden]) {
  animation: motion-typeset-in 480ms var(--motion-expo) both;
}

.campaign-hud:not([hidden]) {
  animation: motion-typeset-in 360ms var(--motion-expo) both;
}

.word-definition-popover:not([hidden]) {
  transform-origin: 32px 0;
  animation: motion-popover-open 300ms var(--motion-expo) both;
}

.overlay.show { animation: motion-scrim-in 260ms ease-out both; }
.overlay.show .overlay-card { animation: motion-result-in 520ms var(--motion-expo) both; }

.campaign-result-stars:not([hidden]) span,
.campaign-result-stars:not([hidden]) {
  animation: motion-typeset-in 420ms 110ms var(--motion-expo) both;
}

@media (prefers-reduced-motion: reduce) {
  .entry-section,
  .margin-column .stats-bar,
  .margin-column .side-actions,
  .margin-column .note-block,
  .chain-word.motion-chain-enter,
  .chain-word.motion-chain-enter::after,
  .chain-arrow.motion-chain-enter,
  .target-letters.motion-target-refresh,
  .stat .value.motion-stat-change,
  .campaign-move-count strong.motion-stat-change,
  .campaign-progress-value.motion-stat-change,
  .message.show.motion-message-enter,
  .hints-panel.show,
  .solve-panel.motion-panel-enter,
  .campaign-home:not([hidden]),
  .campaign-hud:not([hidden]),
  .word-definition-popover:not([hidden]),
  .overlay.show,
  .overlay.show .overlay-card,
  .campaign-result-stars:not([hidden]) {
    animation: none !important;
  }

  .btn,
  .game-mode-btn,
  .diff-btn,
  .level-card,
  .hint-word,
  .input-area input,
  .campaign-reset,
  .campaign-hud button {
    transition: none !important;
  }

  .btn:not(:disabled):hover,
  .level-card:hover:not(:disabled),
  .hint-word:hover:not(:disabled) {
    transform: none;
  }
}