:root {
  --bg: #EAEAEA;
  --panel: #ffffff;
  --panel-soft: #f5f5f5;
  --line: #d0d0d0;
  --line-strong: #b8b8b8;
  --text: #282C34;
  --muted: #5a6069;
  --primary: #14D1D1;
  --primary-soft: rgba(20, 209, 209, 0.12);
  --accent: #FF477E;
  --accent-soft: rgba(255, 71, 126, 0.12);
  --success-bg: rgba(20, 209, 209, 0.1);
  --success-text: #0d9b9b;
  --error-bg: rgba(255, 71, 126, 0.1);
  --error-text: #e03d6a;
  --output-bg: #f8fafa;
  --shadow: 0 12px 28px rgba(40, 44, 52, 0.08);
  --r-xl: 20px;
  --r-lg: 16px;
  --r-md: 12px;
  --r-sm: 10px;
  --font: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(20, 209, 209, 0.08), transparent 28%),
    linear-gradient(180deg, #f2fafa 0%, var(--bg) 100%);
}

/* Ensure transparent logo blends with page background */
.brand-logo {
  background: transparent;
}

.page {
  max-width: 1240px;
  margin: 0 auto;
  padding: 20px;
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}

.brand-logo {
  height: 42px;
  width: auto;
  display: block;
  flex-shrink: 0;
}

/* legacy: .brand-mark kept for compatibility, prefer .brand-logo */
.brand-mark {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--primary) 0%, #2ee5e5 100%);
  display: grid;
  place-items: center;
  color: #fff;
  font-weight: 800;
  box-shadow: 0 10px 20px rgba(20, 209, 209, 0.3);
  text-decoration: none;
}

.brand-copy strong {
  display: block;
  font-size: 20px;
  letter-spacing: -0.03em;
}

.brand-copy span {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-size: 13px;
}

.top-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

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

.nav a,
.nav button,
.lang-switch button,
.chip-btn,
.ghost-btn,
.primary-btn {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text);
  border-radius: 12px;
  padding: 11px 14px;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: 0.18s ease;
  text-decoration: none;
}

.nav a.active,
.nav a:hover,
.nav button.active,
.nav button:hover {
  background: var(--primary-soft);
  color: var(--primary);
  border-color: rgba(20, 209, 209, 0.35);
}

.lang-switch {
  display: flex;
  gap: 8px;
}

.lang-switch button.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.hero {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  box-shadow: var(--shadow);
  padding: 22px;
  margin-bottom: 18px;
}

.hero h1 {
  margin: 0 0 8px;
  font-size: clamp(28px, 4vw, 38px);
  line-height: 1.05;
  letter-spacing: -0.04em;
}

.hero p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.65;
  max-width: 800px;
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 18px;
  align-items: start;
}

/* -----------------------------
   Responsive layout
------------------------------ */
@media (max-width: 1024px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .side {
    order: 2;
  }

  .main {
    order: 1;
  }
}

@media (max-width: 720px) {
  .page {
    padding: 14px;
  }

  .topbar {
    gap: 12px;
  }

  .brand-copy strong {
    font-size: 18px;
  }

  .nav {
    gap: 6px;
  }

  .nav a,
  .nav button,
  .lang-switch button,
  .chip-btn,
  .ghost-btn,
  .primary-btn {
    padding: 10px 12px;
    font-size: 13px;
    border-radius: 12px;
  }

  .card-head {
    flex-wrap: wrap;
    align-items: flex-start;
  }

  .card-head-actions {
    width: 100%;
    justify-content: flex-start;
    flex-wrap: wrap;
  }

  .toolbar {
    flex-wrap: wrap;
    gap: 10px;
  }

  .tool-actions {
    flex-wrap: wrap;
    gap: 8px;
  }

  .hint {
    width: 100%;
  }

  .code-editor {
    min-height: 360px;
  }
}

@media (max-width: 420px) {
  .page {
    padding: 10px;
  }

  .brand-logo {
    height: 36px;
  }

  .brand-copy span {
    font-size: 12px;
  }

  .card-body {
    padding: 14px;
  }

  textarea {
    padding: 14px;
    font-size: 13px;
  }

  .code-editor .code-highlight,
  .code-editor .code-text,
  .code-editor .cpp-code,
  .code-editor .py-code,
  .code-editor .java-code {
    padding: 14px;
    font-size: 13px;
  }
}

.main,
.side {
  display: grid;
  gap: 18px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 18px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, #ffffff 0%, #fafcfc 100%);
}

.card-head-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.chip-btn[aria-pressed="true"] {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.card-head h2,
.card-head h3 {
  margin: 0;
  font-size: 18px;
  letter-spacing: -0.02em;
}

.card-head p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.5;
}

.card-body {
  padding: 18px;
}

.editor-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.chips {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.chip {
  padding: 8px 10px;
  border-radius: 999px;
  background: var(--panel-soft);
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

textarea {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: 16px;
  outline: none;
  resize: vertical;
  padding: 16px;
  font: 14px/1.65 "JetBrains Mono", Consolas, ui-monospace, monospace;
  color: var(--text);
  background: #fff;
}

.code-area {
  min-height: auto;
  background: transparent;
}

/* Sublime-like editor: overlay highlighter + auto formatting */
.code-editor {
  position: relative;
  min-height: 420px;
  border: 1px solid var(--line-strong);
  border-radius: 16px;
  background: var(--editor-bg, #fbfdff);
  overflow: hidden;
  --gutter-w: 54px;
}

.code-gutter {
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--gutter-w);
  margin: 0;
  padding: 16px 10px;
  overflow: hidden;
  white-space: pre;
  text-align: right;
  font: 14px/1.65 "JetBrains Mono", Consolas, ui-monospace, monospace;
  color: var(--editor-gutter, rgba(90, 96, 105, 0.85));
  background: var(--editor-gutter-bg, rgba(255, 255, 255, 0.6));
  border-right: 1px solid var(--editor-border, var(--line));
  pointer-events: none;
  user-select: none;
  z-index: 1;
}

.code-editor .code-highlight {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 16px;
  padding-left: calc(var(--gutter-w) + 16px);
  overflow: auto;
  white-space: pre;
  font: 14px/1.65 "JetBrains Mono", Consolas, ui-monospace, monospace;
  color: var(--text);
  pointer-events: none;
}

.code-editor .code-text {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 16px;
  padding-left: calc(var(--gutter-w) + 16px);
  border: none;
  border-radius: 16px;
  outline: none;
  resize: none;
  background: transparent;
  color: transparent;
  -webkit-text-fill-color: transparent;
  caret-color: var(--text);
  overflow: auto;
  font: 14px/1.65 "JetBrains Mono", Consolas, ui-monospace, monospace;
  white-space: pre;
  word-break: normal;
}

.code-editor .cpp-code {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 16px;
  padding-left: calc(var(--gutter-w) + 16px);
  overflow: auto;
  white-space: pre;
  font: 14px/1.65 "JetBrains Mono", Consolas, ui-monospace, monospace;
  color: var(--text);
  background: transparent;
  z-index: 3;
}

.code-editor .py-code {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 16px;
  padding-left: calc(var(--gutter-w) + 16px);
  overflow: auto;
  white-space: pre;
  font: 14px/1.65 "JetBrains Mono", Consolas, ui-monospace, monospace;
  color: var(--text);
  background: transparent;
  z-index: 3;
}

.code-editor .java-code {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 16px;
  padding-left: calc(var(--gutter-w) + 16px);
  overflow: auto;
  white-space: pre;
  font: 14px/1.65 "JetBrains Mono", Consolas, ui-monospace, monospace;
  color: var(--text);
  background: transparent;
  z-index: 3;
}

.tok-ws {
  display: inline-block;
  width: 1ch;
  text-align: center;
  font-style: normal;
  opacity: 0.22;
  color: var(--editor-ws, rgba(90, 96, 105, 0.65));
}

.code-editor.dark {
  --editor-bg: #0b1220;
  --editor-border: rgba(148, 163, 184, 0.28);
  --editor-gutter: rgba(148, 163, 184, 0.9);
  --editor-gutter-bg: rgba(2, 6, 23, 0.35);
  --editor-ws: rgba(148, 163, 184, 0.9);
}

.code-editor.dark .code-highlight,
.code-editor.dark .cpp-code,
.code-editor.dark .py-code,
.code-editor.dark .java-code {
  color: rgba(226, 232, 240, 0.95);
}

.code-editor.dark .code-text {
  caret-color: #e5e7eb;
}

.code-editor.dark .tok-kw {
  color: #22d3ee;
}
.code-editor.dark .tok-type {
  color: #a78bfa;
}
.code-editor.dark .tok-fn {
  color: #fb7185;
}
.code-editor.dark .tok-bool {
  color: #34d399;
}
.code-editor.dark .tok-num {
  color: #60a5fa;
}
.code-editor.dark .tok-str {
  color: #f472b6;
}
.code-editor.dark .tok-comment {
  color: rgba(148, 163, 184, 0.9);
}
.code-editor.dark .tok-op {
  color: #fb7185;
}
.code-editor.dark .tok-punct {
  color: rgba(226, 232, 240, 0.9);
  opacity: 1;
}

.code-editor .code-text:focus {
  outline: none;
}

/* Token colors (special words + symbols) */
.tok-kw {
  color: var(--primary);
  font-weight: 700;
}

.tok-type {
  color: #7c3aed;
  font-weight: 700;
}

.tok-fn {
  color: var(--accent);
  font-weight: 700;
}

.tok-bool {
  color: #0d9b9b;
  font-weight: 700;
}

.tok-num {
  color: #2563eb;
}

.tok-str {
  color: #db2777;
}

.tok-comment {
  color: var(--muted);
  font-style: italic;
}

.tok-op {
  color: var(--accent);
  font-weight: 700;
}

.tok-punct {
  color: var(--text);
  opacity: 0.9;
}

/* Autocomplete popup (simple Sublime-like suggestions) */
.autocomplete {
  position: absolute;
  top: 10px;
  right: 10px;
  z-index: 5;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: var(--shadow);
  width: 280px;
  max-height: 260px;
  overflow: auto;
}

.autocomplete-list {
  padding: 6px;
}

.autocomplete-item {
  font: 13px/1.6 "JetBrains Mono", Consolas, ui-monospace, monospace;
  padding: 8px 10px;
  border-radius: 10px;
  cursor: pointer;
  white-space: nowrap;
}

.autocomplete-item:hover,
.autocomplete-item.active {
  background: var(--primary-soft);
  color: var(--primary);
}

.input-area {
  min-height: 137px;
}

.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 14px;
}

.tool-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.ghost-btn:hover,
.chip-btn:hover {
  background: var(--panel-soft);
}

.primary-btn {
  background: linear-gradient(135deg, var(--primary) 0%, #2ee5e5 100%);
  border-color: var(--primary);
  color: #fff;
  box-shadow: 0 10px 18px rgba(20, 209, 209, 0.28);
}

.primary-btn:hover {
  filter: brightness(1.05);
}

.hint {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}

.stack {
  display: grid;
  gap: 14px;
}

.status-box,
.output-box,
.error-box {
  border-radius: 16px;
  padding: 14px 16px;
  font: 13px/1.6 "JetBrains Mono", Consolas, ui-monospace, monospace;
  border: 1px solid var(--line);
  min-height: 96px;
  white-space: pre-wrap;
}

.status-box {
  background: var(--success-bg);
  color: var(--success-text);
}

.output-box {
  background: var(--output-bg);
  color: var(--text);
}

.error-box {
  background: var(--error-bg);
  color: var(--error-text);
}

.error-box.compile-success {
  background: var(--success-bg);
  color: var(--success-text);
}

.examples-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 12px;
}

.example-card {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 14px;
  background: #fff;
  cursor: pointer;
  transition: 0.18s ease;
}

.example-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 22px rgba(32, 56, 92, 0.08);
  border-color: #bfd0fb;
}

.example-card strong {
  display: block;
  font-size: 13px;
  margin-bottom: 6px;
}

.example-card span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.5;
}

[data-lang] {
  display: none;
}

body.lang-ru [data-lang="ru"] {
  display: initial;
}

body.lang-kg [data-lang="kg"] {
  display: initial;
}

/* Footer */
.site-footer {
  margin: 18px 0 6px;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  background: var(--panel);
  box-shadow: var(--shadow);
  color: var(--muted);
  font-size: 13px;
  display: flex;
  gap: 8px;
  align-items: center;
  justify-content: center;
}

.site-footer a {
  color: var(--text);
  font-weight: 800;
  text-decoration: none;
  border-bottom: 1px dashed rgba(40, 44, 52, 0.35);
}

.site-footer a:hover {
  color: var(--primary);
  border-bottom-color: rgba(20, 209, 209, 0.7);
}

/* Task context */
.task-context {
  background: var(--panel-soft);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  padding: 14px 18px;
  margin-bottom: 16px;
  font-size: 14px;
}

.task-context code {
  font-family: "JetBrains Mono", Consolas, monospace;
  white-space: pre-wrap;
}

#taskContextStatement {
  white-space: pre-wrap;
}

.task-context-title {
  font-weight: 700;
  margin-bottom: 6px;
}

/* Tasks page */
.tasks-header {
  margin-bottom: 24px;
}

.task-group-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 14px 0 10px;
}

.task-group-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.tasks-header h1 {
  margin: 0 0 8px;
  font-size: clamp(24px, 3vw, 32px);
}

.task-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.task-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 14px 18px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow);
  color: var(--text);
  transition: 0.18s ease;
}

.task-open {
  display: flex;
  align-items: center;
  gap: 16px;
  flex: 1;
  min-width: 0;
  text-decoration: none;
  color: inherit;
}

.task-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.task-solution-btn {
  padding: 6px 10px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 700;
  line-height: 1.2;
}

.task-solution-btn-has {
  background: var(--primary);
  border-color: var(--primary);
  color: #052b2b;
}

.task-id {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--primary-soft);
  border-radius: 12px;
  font-weight: 800;
  color: var(--primary);
}

.task-item:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(40, 44, 52, 0.1);
  border-color: var(--primary);
}

.task-item:hover .task-open {
  color: inherit;
}

.task-content {
  flex: 1;
  min-width: 0;
}

.task-title {
  font-weight: 700;
  margin-bottom: 4px;
}

.task-meta {
  font-size: 13px;
  color: var(--muted);
}

.task-difficulty {
  flex-shrink: 0;
  padding: 6px 12px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 700;
}

.task-difficulty-1 {
  background: #dcfce7;
  color: #166534;
}

.task-difficulty-2 {
  background: #fef3c7;
  color: #92400e;
}

.task-difficulty-3 {
  background: #fee2e2;
  color: #991b1b;
}

/* Modal (solutions) */
.modal-open {
  overflow: hidden;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 18px;
  z-index: 1000;
}

.modal-backdrop[hidden] {
  display: none !important;
}

.modal {
  width: min(860px, 96vw);
  max-height: min(82vh, 720px);
  display: flex;
  flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.25);
}

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

.modal-title {
  font-weight: 800;
  font-size: 14px;
  color: var(--text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.modal-body {
  padding: 12px 14px;
  overflow: auto;
}

.modal-pre {
  margin: 0;
  padding: 12px;
  border-radius: 12px;
  background: rgba(20, 209, 209, 0.06);
  border: 1px solid rgba(20, 209, 209, 0.18);
  font: 13px/1.6 "JetBrains Mono", Consolas, ui-monospace, monospace;
  white-space: pre;
  color: var(--text);
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  padding: 10px 14px 14px;
  border-top: 1px solid var(--line);
}

.modal-close-btn {
  padding: 6px 10px;
  border-radius: 10px;
}

/* Semantics page */
.semantics-header {
  margin-bottom: 24px;
}

.semantics-section {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  padding: 22px;
  margin-bottom: 18px;
  box-shadow: var(--shadow);
}

.semantics-section h2 {
  font-size: 18px;
  margin: 0 0 14px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--primary);
}

.semantics-section h3 {
  font-size: 15px;
  margin: 18px 0 10px;
  color: var(--muted);
}

.syntax-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.syntax-table th,
.syntax-table td {
  padding: 12px 14px;
  text-align: left;
  border-bottom: 1px solid var(--line);
}

.syntax-table th {
  background: var(--panel-soft);
  font-weight: 700;
}

.syntax-table tr:hover td {
  background: var(--panel-soft);
}

.code-block {
  background: #fbfdff;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  padding: 16px;
  font: 13px/1.65 "JetBrains Mono", Consolas, monospace;
  overflow-x: auto;
  margin: 12px 0;
  white-space: pre;
}

/* Inline code / special words on semantics page */
.syntax-table code,
.semantics-section code {
  font-family: "JetBrains Mono", Consolas, monospace;
  font-size: 13px;
  padding: 2px 6px;
  border-radius: 10px;
  background: var(--primary-soft);
  border: 1px solid rgba(20, 209, 209, 0.35);
  color: var(--primary);
  white-space: nowrap;
}

.bilingual {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

@media (max-width: 1080px) {
  .layout {
    grid-template-columns: 1fr;
  }
  .side {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .side .card:first-child {
    grid-column: 1 / -1;
  }
}

@media (max-width: 760px) {
  .page {
    padding: 14px;
  }
  .topbar {
    align-items: flex-start;
  }
  .layout,
  .side,
  .examples-grid {
    grid-template-columns: 1fr;
  }
  .code-area {
    min-height: 320px;
  }
  .toolbar {
    align-items: stretch;
  }
  .tool-actions {
    width: 100%;
  }
  .tool-actions button,
  .tool-actions .primary-btn {
    flex: 1;
  }
  .bilingual {
    grid-template-columns: 1fr;
  }
  .task-item {
    flex-wrap: wrap;
  }
}