:root {
  --canvas: #0d0d0d;
  --surface: #151515;
  --surface-raised: #1b1b1b;
  --surface-hover: #222222;
  --ink: #f2f2ee;
  --muted: #a8a8a2;
  --quiet: #6f716d;
  --line: rgba(255, 255, 255, 0.09);
  --soft-line: rgba(255, 255, 255, 0.055);
  --accent: #10a37f;
  --accent-light: #74e1c2;
  --danger: #ef8d81;
  --blue: #8bb6ff;
  --violet: #c3a7ff;
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 14px;
  font-family: "Manrope", sans-serif;
  color: var(--ink);
  background: var(--canvas);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--canvas);
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(900px 360px at 76% -10%, rgba(16, 163, 127, 0.13), transparent 62%),
    var(--canvas);
  font-size: 15px;
  line-height: 1.5;
}

button,
input {
  font: inherit;
}

button {
  color: inherit;
}

button:focus-visible,
input:focus-visible,
a:focus-visible {
  outline: 2px solid var(--accent-light);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  z-index: 20;
  top: -48px;
  left: 24px;
  padding: 10px 14px;
  border-radius: 10px;
  color: #07100d;
  background: var(--accent-light);
  transition: top 160ms ease;
}

.skip-link:focus {
  top: 16px;
}

.app-shell {
  width: 100%;
  padding: 20px clamp(24px, 4vw, 76px) 48px;
}

.topbar {
  position: sticky;
  z-index: 20;
  top: 0;
  padding-top: 8px;
  background: linear-gradient(180deg, var(--canvas) 78%, rgba(13, 13, 13, 0));
}

.top-trackbar {
  display: flex;
  overflow-x: auto;
  gap: 4px;
  margin: 0 -8px;
  padding: 8px;
  border-top: 1px solid var(--soft-line);
  border-bottom: 1px solid var(--soft-line);
  background: rgba(21, 21, 21, 0.78);
  backdrop-filter: blur(14px);
  scrollbar-width: none;
}

.top-trackbar::-webkit-scrollbar {
  display: none;
}

.top-track-button {
  display: inline-flex;
  min-width: max-content;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  border: 0;
  border-radius: 10px;
  color: var(--muted);
  background: transparent;
  cursor: pointer;
  white-space: nowrap;
  transition: color 160ms ease, background 160ms ease, transform 160ms ease;
}

.top-track-button:hover {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.06);
}

.top-track-button:active {
  transform: scale(0.98);
}

.top-track-button.active {
  color: var(--ink);
  background: rgba(16, 163, 127, 0.16);
}

.top-track-marker {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--quiet);
}

.top-track-marker.mint {
  background: var(--accent);
}

.top-track-marker.blue {
  background: var(--blue);
}

.top-track-marker.violet {
  background: var(--violet);
}

.top-track-button.active .top-track-marker {
  box-shadow: 0 0 0 4px rgba(116, 225, 194, 0.13);
}

.top-track-label {
  font-size: 13px;
  font-weight: 700;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

.panel-kicker {
  margin-bottom: 6px;
  color: var(--quiet);
  font-family: "DM Mono", monospace;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.exercise-zone {
  min-width: 0;
  padding-top: clamp(32px, 4vw, 64px);
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 18px;
}

.section-heading h1 {
  margin-bottom: 0;
  font-size: 23px;
  letter-spacing: -0.055em;
}

.exercise-count {
  flex: 0 0 auto;
  color: var(--quiet);
  font-family: "DM Mono", monospace;
  font-size: 11px;
}

.exercise-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 12px;
}

.exercise-card {
  display: flex;
  min-width: 0;
  min-height: 218px;
  flex-direction: column;
  align-items: flex-start;
  padding: 19px;
  border: 1px solid transparent;
  border-radius: var(--radius-lg);
  color: var(--ink);
  background: var(--surface);
  cursor: pointer;
  text-align: left;
  transition: border-color 180ms ease, background 180ms ease, transform 180ms ease;
}

.exercise-card:hover {
  border-color: var(--line);
  background: var(--surface-hover);
  transform: translateY(-3px);
}

.exercise-card.active {
  border-color: rgba(116, 225, 194, 0.43);
  background: linear-gradient(160deg, rgba(23, 52, 44, 0.72), var(--surface-raised) 60%);
}

.card-topline {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.exercise-number {
  color: var(--quiet);
  font-family: "DM Mono", monospace;
  font-size: 11px;
}

.exercise-kind-icon {
  display: inline-grid;
  width: 30px;
  height: 30px;
  place-items: center;
  border-radius: 9px;
  color: var(--accent-light);
  background: rgba(16, 163, 127, 0.12);
}

.exercise-kind-icon.blue {
  color: var(--blue);
  background: rgba(126, 175, 255, 0.11);
}

.exercise-kind-icon.violet {
  color: var(--violet);
  background: rgba(195, 167, 255, 0.11);
}

.icon {
  width: 17px;
  height: 17px;
  stroke: currentColor;
  stroke-width: 1.8;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.exercise-card h3 {
  overflow: hidden;
  margin: 26px 0 8px;
  font-size: 16px;
  letter-spacing: -0.042em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.exercise-card p {
  display: -webkit-box;
  overflow: hidden;
  margin-bottom: auto;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.58;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.card-meta {
  display: flex;
  width: 100%;
  justify-content: space-between;
  gap: 10px;
  padding-top: 17px;
  color: var(--quiet);
  font-family: "DM Mono", monospace;
  font-size: 10px;
}

.completed-mark {
  color: var(--accent-light);
}

.practice-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(215px, 0.42fr);
  gap: clamp(26px, 5vw, 70px);
  margin-top: 44px;
  padding: clamp(24px, 4vw, 48px);
  border: 1px solid var(--line);
  border-radius: var(--radius-xl);
  background: linear-gradient(135deg, rgba(25, 25, 25, 0.95), rgba(15, 15, 15, 0.98));
  box-shadow: 0 30px 72px rgba(0, 0, 0, 0.25);
}

.practice-content {
  min-width: 0;
}

.practice-title-row {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 16px;
}

.practice-title-row h2 {
  margin-bottom: 0;
  font-size: clamp(26px, 3vw, 39px);
  letter-spacing: -0.065em;
  line-height: 1.05;
}

.timer {
  flex: 0 0 auto;
  padding: 8px 10px;
  border-radius: 9px;
  color: var(--accent-light);
  background: rgba(16, 163, 127, 0.12);
  font-family: "DM Mono", monospace;
  font-size: 11px;
  font-weight: 500;
}

.instruction {
  max-width: 680px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.7;
}

.practice-body {
  margin-top: 31px;
}

.target-phrase {
  margin: 0;
  padding: 20px 0 22px;
  border-top: 1px solid var(--soft-line);
  border-bottom: 1px solid var(--soft-line);
  color: #f8f8f4;
  font-size: clamp(20px, 2.4vw, 29px);
  font-weight: 600;
  letter-spacing: -0.045em;
  line-height: 1.32;
}

.exercise-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  margin-top: 19px;
}

.button {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0 14px;
  border: 0;
  border-radius: 12px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: transform 150ms ease, background 150ms ease, color 150ms ease;
}

.button:active {
  transform: scale(0.975);
}

.button-primary {
  color: #062018;
  background: var(--accent-light);
}

.button-primary:hover {
  background: #a1f0d9;
}

.button-secondary {
  color: var(--ink);
  background: var(--surface-hover);
}

.button-secondary:hover {
  background: #2a2a2a;
}

.answer-line {
  display: flex;
  max-width: 460px;
  gap: 8px;
  margin-top: 19px;
}

.answer-input {
  width: 100%;
  min-width: 0;
  min-height: 44px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  color: var(--ink);
  background: rgba(0, 0, 0, 0.18);
}

.answer-input::placeholder {
  color: var(--quiet);
}

.choice-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 9px;
}

.choice-button {
  min-width: 0;
  min-height: 51px;
  padding: 11px 13px;
  border: 1px solid var(--soft-line);
  border-radius: 12px;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.025);
  cursor: pointer;
  text-align: left;
  transition: border-color 150ms ease, background 150ms ease, color 150ms ease;
}

.choice-button:hover {
  color: var(--ink);
  border-color: var(--line);
  background: rgba(255, 255, 255, 0.055);
}

.choice-button.active {
  border-color: rgba(116, 225, 194, 0.47);
  color: var(--ink);
  background: rgba(16, 163, 127, 0.13);
}

.choice-value {
  display: block;
  overflow: hidden;
  color: var(--ink);
  font-family: "DM Mono", monospace;
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.choice-label {
  display: block;
  overflow: hidden;
  margin-top: 2px;
  color: var(--quiet);
  font-size: 11px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.code-block {
  overflow-x: auto;
  margin: 0 0 18px;
  padding: 16px;
  border-radius: var(--radius-md);
  color: #d7eee7;
  background: #101312;
  font-family: "DM Mono", monospace;
  font-size: 12px;
  line-height: 1.7;
  white-space: pre;
}

.feedback {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
}

.feedback.correct {
  color: var(--accent-light);
}

.feedback.incorrect {
  color: var(--danger);
}

.practice-aside {
  display: flex;
  min-width: 0;
  flex-direction: column;
  justify-content: space-between;
  padding: 22px;
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.035);
}

.aside-description {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.65;
}

.hint {
  margin: 29px 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--soft-line);
  color: var(--quiet);
  font-size: 12px;
  line-height: 1.6;
}

.hint strong {
  display: block;
  margin-bottom: 5px;
  color: var(--muted);
  font-family: "DM Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.timer-start {
  width: 100%;
  margin-top: 28px;
}

.empty-state,
.error-state {
  padding: 38px 0;
  color: var(--muted);
}

.app-loading {
  display: flex;
  min-height: 100vh;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.app-loading span {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
  animation: load-pulse 800ms ease-in-out infinite alternate;
}

.app-loading span:nth-child(2) {
  animation-delay: 120ms;
}

.app-loading span:nth-child(3) {
  animation-delay: 240ms;
}

@keyframes load-pulse {
  to {
    opacity: 0.25;
    transform: translateY(-6px);
  }
}

@media (max-width: 1080px) {
  .exercise-grid {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  }
}

@media (max-width: 840px) {
  .app-shell {
    padding-inline: 24px;
  }

  .top-trackbar {
    margin-inline: -4px;
  }

  .practice-panel {
    grid-template-columns: 1fr;
  }

  .practice-aside {
    gap: 14px;
  }

  .timer-start {
    width: max-content;
    margin-top: 0;
  }
}

@media (max-width: 560px) {
  .app-shell {
    padding: 12px 12px 32px;
  }

  .top-trackbar {
    margin-inline: 0;
    padding: 6px 0;
  }

  .top-track-button {
    padding: 9px 11px;
  }

  .exercise-zone {
    padding-top: 24px;
  }

  .exercise-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 9px;
  }

  .exercise-card {
    min-height: 196px;
    padding: 14px;
    border-radius: 16px;
  }

  .exercise-card h3 {
    margin-top: 22px;
    font-size: 14px;
  }

  .exercise-card p {
    font-size: 11px;
  }

  .card-meta {
    padding-top: 12px;
    font-size: 9px;
  }

  .practice-panel {
    gap: 23px;
    margin-top: 30px;
    padding: 20px;
    border-radius: 22px;
  }

  .practice-title-row {
    align-items: start;
  }

  .timer {
    margin-top: 2px;
  }

  .target-phrase {
    font-size: 20px;
  }

  .choice-list {
    grid-template-columns: 1fr;
  }

  .answer-line {
    flex-direction: column;
  }

  .answer-line .button {
    width: 100%;
  }

  .practice-aside {
    padding: 17px;
  }

  .timer-start {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}