/* Auth shares the landing's palette and controls, isolated from legacy button motion. */
.auth-layout { display: grid; place-items: center; min-height: 100dvh; padding: 24px; background: var(--white); }
.auth-page {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  width: min(960px, 100%);
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--white);
  color: var(--ink);
  box-shadow: 0 8px 0 var(--blue);
}
.auth-intro {
  z-index: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  margin: 10px;
  border-radius: 16px;
  padding: 28px;
  background: var(--brand-field);
}
.auth-brand { display: inline-flex; align-items: center; gap: 10px; width: fit-content; font-size: 1.2rem; font-weight: 800; letter-spacing: -.04em; }
.auth-brand img { width: 32px; height: 32px; }
.auth-story { display: flex; flex-direction: column; flex: 1; min-height: 0; }
.auth-story--signup, .auth-page--signup .auth-story--login { display: none; }
.auth-page--signup .auth-story--signup { display: flex; }
.auth-story-copy { margin-top: 28px; }
.auth-kicker { margin-bottom: 14px; color: var(--ink); font-size: .75rem; font-weight: 700; }
.auth-intro h1 { font-size: clamp(2.4rem, 3.8vw, 3.1rem); font-weight: 800; letter-spacing: -.065em; line-height: 1.02; }
.auth-story-copy > p:last-child { max-width: 30ch; margin-top: 18px; color: var(--ink); font-size: .9rem; line-height: 1.7; }
.auth-study-scene { width: min(100%, 330px); margin: auto; padding-block: 20px 16px; }
.auth-lesson-card, .auth-plan-card { position: relative; border-radius: 14px; padding: 20px; background: white; box-shadow: 0 8px 0 var(--primary); }
.auth-paper-top { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 18px; color: var(--muted); font-size: .65rem; font-weight: 700; }
.auth-paper-top img { width: 28px; height: 28px; }
.auth-lesson-card strong, .auth-plan-card strong { display: block; color: var(--ink); font-size: 1.55rem; letter-spacing: -.055em; line-height: 1.15; }
.auth-learning-steps { display: flex; justify-content: space-between; gap: 8px; margin-top: 30px; color: var(--ink); font-size: .65rem; font-weight: 700; }
.auth-learning-steps span:last-child { color: var(--muted); }
.auth-learning-progress { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; margin-top: 10px; }
.auth-learning-progress i { height: 6px; border-radius: 3px; background: var(--progress); }
.auth-learning-progress i:last-child { background: var(--line); }
.auth-source-tabs { display: flex; gap: 6px; padding-inline: 10px; }
.auth-source-tabs span { flex: 1; border-radius: 8px 8px 0 0; padding: 10px 5px; background: var(--blue); color: var(--ink); font-size: .6rem; font-weight: 700; text-align: center; }
.auth-source-tabs span:nth-child(2) { background: var(--progress); }
.auth-plan-card .auth-paper-top { margin-bottom: 18px; }
.auth-plan-topic { display: flex; align-items: center; gap: 10px; margin-top: 12px; border-top: 1px solid var(--line); padding-top: 8px; color: var(--ink); font-size: .7rem; font-weight: 600; }
.auth-plan-topic > span:first-child { color: var(--primary-hover); font-size: .6rem; }
.auth-plan-topic > span:last-child { margin-left: auto; }
.auth-scene-caption { margin-top: 18px; color: var(--ink); font-size: .7rem; text-align: center; }
.auth-back { width: fit-content; margin-top: 8px; font-size: .75rem; font-weight: 700; }
.auth-back:hover { text-decoration: underline; text-underline-offset: 4px; }
.auth-panel { display: grid; align-content: center; min-width: 0; padding: 32px clamp(24px, 3.5vw, 44px); }
.auth-panel[hidden] { visibility: hidden; pointer-events: none; }
.auth-forms { grid-column: 2; grid-row: 1; display: grid; min-width: 0; }
.auth-forms .auth-panel { grid-column: 1; grid-row: 1; }
.auth-page--switchable .auth-intro { grid-column: 1; grid-row: 1; }
.auth-page--switchable .auth-intro, .auth-forms { transition: transform 280ms cubic-bezier(.77, 0, .175, 1); }
.auth-page--instant .auth-intro, .auth-page--instant .auth-forms { transition: none; }
.auth-page--signup .auth-intro { transform: translateX(calc(100% + 20px)); }
.auth-page--signup .auth-forms { transform: translateX(-100%); }
.auth-panel-copy { display: grid; gap: 12px; }
.auth-panel-copy .auth-eyebrow { color: var(--primary-hover); font-size: .75rem; font-weight: 700; }
.auth-panel h2 { margin: 0; white-space: pre-line; font-size: clamp(2rem, 3vw, 2.4rem); font-weight: 800; letter-spacing: -.055em; line-height: 1.05; }
.auth-panel-copy > p:last-child { font-size: .85rem; line-height: 1.65; text-wrap: pretty; }
.auth-form { display: grid; gap: 12px; margin-top: 22px; }
.auth-form .field { gap: 6px; }
.auth-form .field label { font-size: .8rem; font-weight: 700; }
.auth-form input { min-height: 48px; padding: 12px 14px; border-color: var(--line); border-radius: 10px; font-size: .9rem; }
.auth-form input::placeholder { color: var(--muted); opacity: 1; }
.auth-form input:focus { border-color: var(--ink); box-shadow: none; }
.auth-form input:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
.auth-password-label { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; }
.auth-password-label .text-link { font-size: .7rem; font-weight: 700; }
.auth-form :is(.button, .landing-button) { width: 100%; min-height: 50px; margin-top: 4px; padding: 12px 20px; border: 2px solid var(--ink); border-radius: 999px; background: var(--ink); color: white; font-size: .9rem; font-weight: 800; box-shadow: none; filter: none; transform: none; transition: background 180ms ease, color 180ms ease; }
.auth-form-note { margin-top: 14px; font-size: .7rem; line-height: 1.7; }
.auth-switch { margin-top: 20px; border-top: 1px solid var(--line); padding-top: 16px; font-size: .8rem; }
.auth-switch a { margin-left: 4px; color: var(--ink); font-weight: 800; }
@media (hover: hover) and (pointer: fine) {
  .auth-form :is(.button, .landing-button):hover { background: white; color: var(--ink); border-color: var(--ink); box-shadow: none; filter: none; transform: none; }
}
@media (max-width: 760px) {
  .auth-page--switchable .auth-intro, .auth-forms { transition: none; }
  .auth-layout { padding: 20px 16px; }
  .auth-page { grid-template-columns: minmax(0, 1fr); width: min(440px, 100%); border-radius: 20px; }
  .auth-intro, .auth-page--signup .auth-intro { grid-column: 1; grid-row: 1; margin: 0; border-radius: 20px 20px 0 0; padding: 20px 24px; background: var(--brand-field); transform: none; }
  .auth-intro .auth-story, .auth-back { display: none; }
  .auth-panel { grid-column: 1; grid-row: 2; padding: 24px; }
  .auth-forms, .auth-page--signup .auth-forms { grid-column: 1; grid-row: 2; transform: none; }
  .auth-forms .auth-panel { grid-row: 1; }
  .auth-panel[hidden] { display: none; }
  .auth-panel h2 { font-size: clamp(1.9rem, 8vw, 2.25rem); }
}
@media (prefers-reduced-motion: reduce) {
  .auth-page--switchable .auth-intro, .auth-forms { transition: none; }
}