html,
body {
  min-height: 100%;
}

html body {
  margin: 0;
  background: var(--surface-cool);
}

body #app {
  display: block;
  width: 100%;
  min-height: calc(100vh - 220px);
  padding: 0;
}

.flashcards-site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: saturate(180%) blur(12px);
}

.flashcards-site-header__inner {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  width: 100%;
  max-width: 1120px;
  min-height: var(--header-h);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.flashcards-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink-900);
  text-decoration: none;
}

.flashcards-site-header .bar-image {
  width: 32px;
  height: 32px;
  border-radius: 7px;
}

.flashcards-site-header .bar-text {
  margin: 0;
  color: var(--ink-900);
  font-size: 1.125rem;
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1;
  white-space: nowrap;
}

.flashcards-site-header .bc_text {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  background: var(--brand-100);
  color: var(--brand-800);
  font-size: 0.75rem;
  font-weight: 800;
  line-height: 1.2;
  white-space: nowrap;
}

.flashcards-site-header .premium-crown {
  font-size: 1.25rem;
  line-height: 1;
}

.flashcards-page {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: clamp(2rem, 5vw, 3.75rem) var(--gutter) clamp(3rem, 7vw, 5rem);
}

.flashcards-intro {
  max-width: 760px;
  margin: 0 auto clamp(1.75rem, 4vw, 2.75rem);
  text-align: center;
}

.flashcards-eyebrow {
  margin: 0 0 0.5rem;
  color: var(--brand-700);
  font-size: 0.8125rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  line-height: 1.3;
  text-transform: uppercase;
}

.flashcards-intro h1 {
  margin-bottom: 0.75rem;
  font-size: clamp(2rem, 5vw, 3rem);
}

.flashcards-intro > p:last-child {
  max-width: 680px;
  margin: 0 auto;
  color: var(--ink-500);
  font-size: var(--step-1);
  line-height: 1.6;
}

.flashcards-state,
.flashcards-workspace {
  width: 100%;
}

.flashcards-state {
  min-height: 320px;
  padding: 3rem 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: #fff;
  box-shadow: var(--shadow-sm);
  text-align: center;
}

.flashcards-loading {
  margin-bottom: 1rem;
  color: var(--ink-700);
  font-weight: 700;
}

.flashcards-toolbar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  grid-template-areas: "back progress restart";
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.85rem;
}

.flashcards-back {
  grid-area: back;
  justify-self: start;
}

.flashcards-restart {
  grid-area: restart;
  justify-self: end;
}

.flashcards-progress-copy {
  grid-area: progress;
  display: flex;
  flex-direction: column;
  align-items: center;
  color: var(--ink-500);
  font-size: 0.8125rem;
  line-height: 1.35;
  text-align: center;
}

.flashcards-progress-copy strong {
  color: var(--ink-900);
  font-size: 0.9375rem;
}

.flashcards-progress-track {
  width: 100%;
  height: 7px;
  margin-bottom: 1rem;
  overflow: hidden;
  border-radius: 999px;
  background: var(--line);
}

.flashcards-progress-track span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: var(--brand-700);
  transition: width 0.2s ease;
}

.flash-card-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  min-height: 44px;
  padding: 0.7rem 1rem;
  border: 1px solid var(--brand-700);
  border-radius: var(--radius-sm);
  background: var(--brand-700);
  color: #fff;
  font: inherit;
  font-size: 0.9375rem;
  font-weight: 800;
  line-height: 1.15;
  cursor: pointer;
  transition: background-color 0.18s ease, border-color 0.18s ease, transform 0.18s ease;
}

.flash-card-button:hover:not(:disabled) {
  border-color: var(--brand-800);
  background: var(--brand-800);
  transform: translateY(-1px);
}

.button-icon {
  font-size: 1.1rem;
  line-height: 1;
}

.flash-card-button--secondary {
  border-color: var(--line-strong);
  background: #fff;
  color: var(--brand-800);
}

.flash-card-button--secondary:hover:not(:disabled) {
  border-color: var(--brand-600);
  background: var(--surface-cool);
}

.flash-card-button:disabled {
  border-color: var(--line);
  background: var(--surface-warm);
  color: var(--ink-300);
  cursor: not-allowed;
}

.flash-card {
  width: 100%;
  min-height: 430px;
  margin: 0;
  perspective: 1200px;
  touch-action: pan-y;
}

.flash-card-inner,
.reveal-mode-flash-card {
  position: relative;
  width: 100%;
  min-height: inherit;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: #fff;
  box-shadow: var(--shadow);
}

.flash-card-inner {
  height: 430px;
  text-align: center;
  transform-style: preserve-3d;
  cursor: pointer;
  transition: transform 0.55s ease;
}

.flash-card-front,
.flash-card-back {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: clamp(1.5rem, 4vw, 3rem);
  overflow: hidden;
  border-radius: inherit;
  background: #fff;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

.flash-card-front {
  gap: 1.2rem;
  background:
    radial-gradient(circle at 50% 44%, rgba(185, 226, 234, 0.45), transparent 35%),
    #fff;
}

.flash-card-back {
  transform: rotateY(180deg);
}

.flash-card-kicker {
  color: var(--brand-700);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  line-height: 1.3;
  text-transform: uppercase;
}

.flash-card-image {
  display: block;
  width: auto;
  max-width: min(280px, 70%);
  max-height: 245px;
  margin: 0 auto;
  object-fit: contain;
}

.signs-heading,
.reveal-mode-signs-heading {
  margin: 0.4rem 0 0.75rem;
  color: var(--ink-900);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 900;
  line-height: 1.2;
}

.signs-explanation,
.reveal-mode-signs-explanation {
  max-width: 620px;
  margin: 0;
  color: var(--ink-700);
  font-size: clamp(1rem, 2vw, 1.125rem);
  font-weight: 400;
  line-height: 1.65;
}

.flash-card-tap-hint {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  margin-top: 0.5rem;
  color: var(--ink-500);
  font-size: 0.875rem;
  font-weight: 600;
}

.reveal-mode-flash-card {
  overflow: hidden;
}

.reveal-mode-flash-card-front {
  display: grid;
  grid-template-columns: minmax(260px, 40%) 1fr;
  min-height: inherit;
}

.reveal-mode-image-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 0;
  padding: clamp(1.5rem, 4vw, 2.75rem);
  background:
    radial-gradient(circle, rgba(185, 226, 234, 0.7), transparent 67%),
    var(--surface-cool);
}

.reveal-mode-traffic-image {
  display: block;
  width: auto;
  max-width: 100%;
  max-height: 270px;
  object-fit: contain;
}

.reveal-mode-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  min-width: 0;
  padding: clamp(1.75rem, 4vw, 3rem);
  text-align: left;
}

.flashcards-controls {
  display: grid;
  grid-template-columns: minmax(230px, 1fr) auto minmax(230px, 1fr);
  align-items: center;
  margin-top: 1rem;
}

.flash-card-checkbox-label {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  justify-self: start;
  min-height: 48px;
  cursor: pointer;
}

.big-checkbox {
  position: relative;
  flex: 0 0 auto;
  width: 46px;
  height: 26px;
  margin: 0;
  border: 1px solid var(--ink-300);
  border-radius: 999px;
  appearance: none;
  background: var(--line-strong);
  cursor: pointer;
  transition: background-color 0.18s ease, border-color 0.18s ease;
}

.big-checkbox::after {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 1px 3px rgba(11, 22, 32, 0.25);
  content: "";
  transition: transform 0.18s ease;
}

.big-checkbox:checked {
  border-color: var(--brand-700);
  background: var(--brand-700);
}

.big-checkbox:checked::after {
  transform: translateX(20px);
}

.flash-card-checkbox-copy {
  display: flex;
  flex-direction: column;
  color: var(--ink-900);
  font-size: 0.9375rem;
  line-height: 1.3;
}

.flash-card-checkbox-copy small {
  margin-top: 0.1rem;
  color: var(--ink-500);
  font-size: 0.75rem;
}

.flash-card-buttons-center {
  grid-column: 2;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
}

.flash-card-button--nav {
  min-width: 112px;
}

.flash-card-question-number {
  display: flex;
  align-items: baseline;
  justify-content: center;
  min-width: 72px;
  color: var(--ink-500);
  line-height: 1;
  text-align: center;
}

.flash-card-question-number strong {
  color: var(--ink-900);
  font-size: 1.35rem;
}

.flash-card-question-number span {
  font-size: 0.9375rem;
}

.flashcards-swipe-hint {
  display: none;
  margin: 1rem 0 0;
  color: var(--ink-500);
  font-size: 0.8125rem;
  line-height: 1.45;
  text-align: center;
}

body .bottom-panel {
  width: 100%;
  margin: 0;
  padding: clamp(2rem, 4vw, 2.75rem) var(--gutter);
  background: var(--brand-900);
  color: #b9d0d6;
  font-size: var(--step--1);
  line-height: 1.55;
  text-align: center;
}

body .bottom-panel > p {
  max-width: 960px;
  margin: 0 auto 0.45rem;
}

body .bottom-links {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.35rem 1.25rem;
  margin-top: 0.9rem;
}

body .bottom-links a {
  min-height: 24px;
  color: #b9d0d6;
  font-weight: 700;
}

@media (max-width: 760px) {
  .flashcards-page {
    padding-top: 2rem;
  }

  .flashcards-intro > p:last-child {
    font-size: 1rem;
  }

  .flashcards-toolbar {
    grid-template-columns: 1fr 1fr;
    grid-template-areas:
      "progress progress"
      "back restart";
    gap: 0.75rem;
  }

  .flashcards-back,
  .flashcards-restart {
    width: 100%;
  }

  .flashcards-restart {
    justify-self: stretch;
  }

  .flashcards-controls {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .flash-card-checkbox-label {
    width: 100%;
    padding: 0.55rem 0.75rem;
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    background: #fff;
  }

  .flash-card-buttons-center {
    grid-column: 1;
    width: 100%;
  }

  .flash-card-button--nav {
    flex: 1 1 0;
  }

  .flashcards-swipe-hint {
    display: block;
  }
}

@media (max-width: 600px) {
  .flashcards-site-header__inner {
    min-height: 64px;
    padding-right: 1rem;
    padding-left: 1rem;
  }

  .flashcards-site-header .bar-image {
    width: 28px;
    height: 28px;
  }

  .flashcards-site-header .bar-text {
    font-size: 1rem;
  }

  .flashcards-page {
    padding-right: 1rem;
    padding-left: 1rem;
  }

  .flash-card {
    min-height: 500px;
  }

  .flash-card-inner {
    height: 500px;
  }

  .reveal-mode-flash-card-front {
    grid-template-columns: 1fr;
    grid-template-rows: minmax(190px, auto) auto;
  }

  .reveal-mode-image-container {
    min-height: 190px;
    padding: 1.25rem;
  }

  .reveal-mode-traffic-image {
    max-width: 58%;
    max-height: 175px;
  }

  .reveal-mode-text {
    justify-content: flex-start;
    padding: 1.5rem;
    text-align: center;
    align-items: center;
  }

  .signs-explanation,
  .reveal-mode-signs-explanation {
    line-height: 1.55;
  }
}

@media (max-width: 440px) {
  .flashcards-site-header .bar-text {
    display: none;
  }

  .flashcards-site-header .bc_text {
    margin-left: 0;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .flashcards-intro h1 {
    font-size: 1.875rem;
  }

  .flash-card-button--nav {
    min-width: 0;
    padding-right: 0.75rem;
    padding-left: 0.75rem;
  }

  .flash-card-question-number {
    min-width: 54px;
  }
}

@media (max-width: 360px) {
  .flash-card-button--nav span {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
  }
}