:root {
  --bg: #070a0f;
  --panel: #111722;
  --panel-2: #0c111a;
  --ink: #eef4ff;
  --muted: #95a0b3;
  --line: #243044;
  --accent: #22c55e;
  --accent-strong: #16a34a;
  --accent-soft: rgba(34, 197, 94, 0.13);
  --warn: #f59e0b;
  --warn-bg: rgba(245, 158, 11, 0.12);
  --error: #ff4d5e;
  --ok: #35d07f;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at top left, rgba(34, 197, 94, 0.1), transparent 32rem), var(--bg);
  color: var(--ink);
}

button,
select,
textarea {
  font: inherit;
}

.app-shell {
  width: min(100vw - 24px, 1880px);
  margin: 0 auto;
  padding: 12px 0 18px;
}

.topbar,
.prompt-panel,
.compiler-panel,
.question-list {
  background: rgba(17, 23, 34, 0.92);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.22);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 16px 18px;
  margin-bottom: 12px;
}

h1,
h2,
p {
  margin: 0;
}

h1 {
  font-size: clamp(1.65rem, 2.6vw, 2.35rem);
  line-height: 1.05;
}

h2 {
  font-size: 1.25rem;
  line-height: 1.25;
}

.eyebrow {
  color: var(--accent);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
  margin-bottom: 6px;
}

.scoreboard {
  min-width: 92px;
  text-align: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 14px;
  background: var(--panel-2);
}

.progress-tools {
  display: flex;
  align-items: center;
  gap: 10px;
}

.progress-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.topnav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.topnav a {
  min-height: 38px;
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 9px 14px;
  background: #0a0f17;
  color: var(--ink);
  font-weight: 800;
  text-decoration: none;
}

.topnav a:hover {
  border-color: rgba(34, 197, 94, 0.5);
  color: var(--accent);
}

.hamburger-btn,
.drawer-backdrop {
  display: none;
}

.hamburger-btn {
  width: 42px;
  height: 42px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #0a0f17;
  cursor: pointer;
}

.hamburger-btn span {
  width: 18px;
  height: 2px;
  border-radius: 999px;
  background: var(--ink);
}

.scoreboard span {
  display: block;
  font-size: 1.5rem;
  font-weight: 800;
}

.scoreboard small {
  color: var(--muted);
}

.layout {
  display: grid;
  grid-template-columns: 340px minmax(0, 1fr);
  gap: 12px;
}

.question-list {
  height: calc(100vh - 112px);
  min-height: 620px;
  overflow: hidden;
  position: sticky;
  top: 10px;
}

.rail-title {
  padding: 16px 16px 10px;
  border-bottom: 1px solid var(--line);
}

.rail-title h2 {
  font-size: 1.15rem;
}

.list-header {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  align-items: center;
  padding: 12px 14px;
  border-bottom: 1px solid var(--line);
}

select {
  min-width: 132px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 8px 10px;
  background: #0a0f17;
  color: var(--ink);
}

.question-buttons {
  height: calc(100% - 119px);
  overflow: auto;
  padding: 10px;
}

.question-pill {
  width: 100%;
  min-height: 44px;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 10px;
  border: 1px solid transparent;
  border-radius: 6px;
  background: transparent;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
}

.question-pill:hover,
.question-pill.active {
  background: var(--accent-soft);
  border-color: rgba(34, 197, 94, 0.42);
}

.question-pill.solved::after {
  content: "✓";
  margin-left: auto;
  color: var(--ok);
  font-weight: 900;
}

.workspace {
  display: grid;
  gap: 12px;
}

.prompt-panel,
.compiler-panel {
  padding: 16px;
}

.prompt-top,
.actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.nav-actions {
  display: flex;
  gap: 8px;
}

.icon-btn {
  width: 38px;
  height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #0a0f17;
  color: var(--ink);
  font-size: 1.6rem;
  line-height: 1;
  cursor: pointer;
}

.expected-output {
  margin-top: 14px;
  padding: 13px;
  background: #0a0f17;
  border: 1px solid var(--line);
  border-radius: 6px;
}

.expected-output span,
label {
  display: block;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
  margin-bottom: 8px;
}

code,
pre,
textarea {
  font-family: "Cascadia Code", Consolas, "Courier New", monospace;
}

.expected-output code {
  white-space: pre-wrap;
  color: var(--ink);
}

.ghost-btn,
.secondary-btn,
.primary-btn {
  border: 1px solid var(--line);
  border-radius: 6px;
  min-height: 38px;
  padding: 9px 14px;
  cursor: pointer;
}

.ghost-btn,
.secondary-btn {
  background: #0a0f17;
  color: var(--ink);
}

.primary-btn {
  background: var(--accent);
  border-color: var(--accent);
  color: #052e16;
  font-weight: 900;
}

.primary-btn:hover {
  background: var(--accent-strong);
}

textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 14px;
  resize: vertical;
  background: #080d14;
  color: var(--ink);
  line-height: 1.5;
}

.source-cache {
  display: none;
}

#compilerOutput {
  min-height: 86px;
}

.warning {
  margin-bottom: 10px;
  padding: 10px 12px;
  border: 1px solid rgba(245, 158, 11, 0.5);
  border-radius: 6px;
  background: var(--warn-bg);
  color: var(--warn);
  font-weight: 700;
}

.embedded-compiler {
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 12px;
  background: #080d14;
}

.compiler-frame-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.compiler-tools {
  display: flex;
  align-items: center;
  gap: 10px;
}

.compiler-frame-head a {
  color: var(--accent);
  font-size: 0.9rem;
  font-weight: 800;
  text-decoration: none;
}

.compiler-frame {
  width: 100%;
  height: min(68vh, 760px);
  min-height: 620px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #05070b;
}

.actual-output {
  margin-top: 12px;
}

.comparison-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 12px;
}

.comparison-panel div {
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 12px;
  background: #080d14;
}

.comparison-panel span {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.comparison-panel code {
  display: block;
  white-space: pre-wrap;
}

#comparisonActual.unmatched {
  color: var(--error);
  font-weight: 800;
}

.actions {
  margin-top: 14px;
  justify-content: flex-start;
  flex-wrap: wrap;
}

#resultMessage {
  color: var(--muted);
  font-weight: 800;
}

#resultMessage.ok {
  color: var(--ok);
}

#resultMessage.bad {
  color: var(--error);
}

.sparkles {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 100;
  overflow: hidden;
}

.sparkles.active {
  background: rgba(0, 0, 0, 0.18);
}

.sparkle {
  position: absolute;
  width: 8px;
  height: 16px;
  border-radius: 2px;
  background: var(--confetti, #22c55e);
  opacity: 0;
  animation: confetti-fall 1700ms cubic-bezier(0.16, 0.9, 0.32, 1) forwards;
}

@keyframes confetti-fall {
  0% {
    transform: translate3d(0, -14vh, 0) rotate(0deg);
    opacity: 0;
  }
  12% {
    opacity: 1;
  }
  100% {
    transform: translate3d(var(--drift), 112vh, 0) rotate(var(--spin));
    opacity: 0;
  }
}

@media (max-width: 1100px) {
  .layout {
    grid-template-columns: 280px minmax(0, 1fr);
  }
}

@media (max-width: 900px) {
  body.question-drawer-open {
    overflow: hidden;
  }

  .layout,
  .comparison-panel {
    grid-template-columns: 1fr;
  }

  .hamburger-btn {
    display: inline-flex;
  }

  .question-list {
    width: min(86vw, 340px);
    height: 100vh;
    min-height: 0;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 80;
    border-radius: 0 8px 8px 0;
    transform: translateX(-105%);
    transition: transform 220ms ease;
  }

  body.question-drawer-open .question-list {
    transform: translateX(0);
  }

  .drawer-backdrop {
    position: fixed;
    inset: 0;
    z-index: 70;
    border: 0;
    background: rgba(0, 0, 0, 0.56);
    cursor: pointer;
  }

  body.question-drawer-open .drawer-backdrop {
    display: block;
  }

  .question-buttons {
    display: block;
    height: calc(100% - 119px);
    max-height: none;
    overflow: auto;
  }

  .question-pill span:last-child {
    display: inline;
  }

  .compiler-frame {
    height: 640px;
    min-height: 560px;
  }
}

@media (max-width: 560px) {
  .app-shell {
    width: min(100vw - 12px, 1880px);
    padding-top: 6px;
  }

  .topbar {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: start;
    gap: 12px;
    padding: 14px;
  }

  h1 {
    font-size: 1.65rem;
  }

  .title-block {
    min-width: 0;
  }

  .progress-tools {
    grid-column: 1 / -1;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
  }

  .topnav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
  }

  .topnav a:last-child {
    grid-column: 1 / -1;
  }

  .topnav a,
  #clearProgress {
    min-height: 36px;
    padding: 8px 11px;
    font-size: 0.9rem;
    justify-content: center;
  }

  .progress-row {
    justify-content: space-between;
    align-items: stretch;
  }

  .progress-row #clearProgress {
    flex: 1;
  }

  .progress-row .scoreboard {
    min-width: 76px;
    padding: 8px 10px;
  }

  .scoreboard span {
    font-size: 1.25rem;
  }

  .compiler-frame-head,
  .compiler-tools {
    align-items: flex-start;
    flex-direction: column;
  }
}