:root {
  color-scheme: dark;

  --bg: #222222;
  --panel: #333333;
  --panel-header: #2b2b2b;
  --border: #444444;
  --border-hover: #666666;
  --border-subtle: #30363d;
  --table-border: #586069;
  --hr-border: #4b5563;

  --text: #d5d5d5;
  --text-bright: #e6edf3;
  --text-strong: #f5f5f5;
  --text-subtle: #c0c0c0;
  --text-muted: #8b949e;
  --text-soft: #aaaaaa;

  --accent: #0099e5;
  --accent-bg: rgba(0, 153, 229, 0.14);
  --link: #0099cc;
  --link-hover: #79c0ff;
  --danger: #ff7b72;
  --danger-bg: rgba(255, 123, 114, 0.12);

  --button-hover: #3a3a3a;
  --code-bg: #0d1117;
  --inline-code-bg: #161b22;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
}

body {
  min-height: 100vh;
  background-color: var(--bg);
  color: var(--text);
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji",
    "Segoe UI Symbol";
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.5;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

.page {
  min-height: 100vh;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.header-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.toolbox-title {
  margin: 0;
  font-size: 1.9rem;
  font-weight: 500;
  color: var(--text);
  position: relative;
  padding-bottom: 0.25rem;
}

.toolbox-title::after {
  content: "";
  display: block;
  width: 100%;
  height: 2px;
  margin-top: 0.15rem;
  background-color: var(--accent);
}

.header-return {
  font-size: 0.9rem;
  white-space: nowrap;
}

.tagline {
  margin: 0 0 1.2rem;
  font-size: 0.9rem;
  color: #c0c0c0;
}

.intro {
  margin: 0 0 1.5rem;
  font-size: 0.95rem;
  color: var(--text-subtle);
}

.subtle-text {
  color: var(--text-muted);
}

/* Toolbar */

.toolbar-shell {
  margin-bottom: 1rem;
}

.toolbar-shell .toolbar {
  margin-bottom: 0;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.75rem;
  margin-bottom: 1rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background-color: var(--panel);
  font-size: 0.8rem;
}

.toolbar-label {
  margin-right: 0.5rem;
}

.toolbar-label-desktop {
  display: inline-block;
  order: 0;
}

/*
  Desktop intentionally looks like the original simple toolbar:
  one Format label, then all buttons in a single row.
*/
.toolbar-group {
  display: contents;
}

.toolbar-group-label {
  display: none;
}

.toolbar-buttons {
  display: contents;
}

.toolbar [data-action="bold"] {
  order: 1;
}

.toolbar [data-action="italic"] {
  order: 2;
}

.toolbar [data-action="heading"] {
  order: 3;
}

.toolbar [data-action="link"] {
  order: 4;
}

.toolbar [data-action="code"] {
  order: 5;
}

.toolbar [data-action="codeblock"] {
  order: 6;
}

.toolbar [data-action="table"] {
  order: 7;
}

.toolbar-spacer {
  flex: 1 1 auto;
  order: 8;
}

#undo-markdown {
  order: 9;
}

#copy-markdown {
  order: 10;
}

#reset-markdown {
  order: 11;
}

.mobile-view-card {
  display: none;
}

.top-btn,
.md-btn {
  cursor: pointer;
  border-radius: 6px;
  border: 1px solid #555555;
  background-color: var(--panel);
  color: var(--text);
  font-family: inherit;
  transition:
    background-color 0.15s ease-out,
    border-color 0.15s ease-out,
    color 0.15s ease-out,
    transform 0.08s ease-out;
}

.top-btn {
  padding: 0.3rem 0.8rem;
  font-size: 0.8rem;
  white-space: nowrap;
}

.md-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  padding: 0.2rem 0.65rem;
  font-size: 0.75rem;
}

.top-btn:hover,
.md-btn:hover {
  background-color: var(--button-hover);
  border-color: var(--border-hover);
  transform: translateY(-0.5px);
}

.top-btn-danger {
  border-color: var(--danger);
  color: var(--danger);
  background-color: transparent;
}

.top-btn-danger:hover {
  background-color: var(--danger-bg);
  border-color: var(--danger);
  color: var(--danger);
}

.top-btn:disabled,
.md-btn:disabled {
  cursor: not-allowed;
  opacity: 0.45;
  transform: none;
}

.top-btn:disabled:hover,
.md-btn:disabled:hover {
  background-color: var(--panel);
  border-color: #555555;
  transform: none;
}

.mobile-toggle.is-active {
  border-color: var(--accent);
  color: var(--accent);
  background-color: var(--accent-bg);
}

.top-btn:focus-visible,
.md-btn:focus-visible,
#markdown-input:focus-visible,
#markdown-preview:focus-visible,
.header-return:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Layout */

.viewer-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  height: clamp(420px, 70vh, 780px);
  min-height: 0;
}

.panel {
  display: flex;
  flex-direction: column;
  min-height: 0;
  border-radius: 6px;
  border: 1px solid var(--border);
  background-color: var(--panel);
  overflow: hidden;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  padding: 0.45rem 0.75rem;
  border-bottom: 1px solid var(--border);
  background-color: var(--panel-header);
  font-size: 0.75rem;
}

.panel-header-title {
  text-transform: uppercase;
  letter-spacing: 0.09em;
  font-size: 0.72rem;
  color: var(--text-soft);
}

.panel-header-meta {
  font-size: 0.72rem;
  color: #888888;
  text-align: right;
}

.panel-body {
  flex: 1 1 auto;
  min-height: 0;
  padding: 0.75rem 0.75rem 0.85rem;
  font-size: 0.85rem;
  overflow: hidden;
}

#markdown-input {
  display: block;
  width: 100%;
  height: 100%;
  min-height: 0;
  border: none;
  outline: none;
  background: transparent;
  color: var(--text-bright);
  font-family:
    ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
  font-size: 0.85rem;
  line-height: 1.4;
  resize: none;
  overflow: auto;
}

#markdown-preview {
  width: 100%;
  height: 100%;
  min-height: 0;
  overflow: auto;
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--text-bright);
}

footer {
  margin-top: 0.75rem;
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* Markdown preview content */

#markdown-preview h1,
#markdown-preview h2,
#markdown-preview h3,
#markdown-preview h4,
#markdown-preview h5,
#markdown-preview h6 {
  font-weight: 600;
  margin-top: 1.1rem;
  margin-bottom: 0.45rem;
  color: var(--text-strong);
}

#markdown-preview h1:first-child,
#markdown-preview h2:first-child,
#markdown-preview h3:first-child {
  margin-top: 0;
}

#markdown-preview h1 {
  font-size: 1.4rem;
}

#markdown-preview h2 {
  font-size: 1.2rem;
}

#markdown-preview h3 {
  font-size: 1.05rem;
}

#markdown-preview p {
  margin: 0.45rem 0;
}

#markdown-preview ul,
#markdown-preview ol {
  padding-left: 1.6rem;
  margin-top: 0.35rem;
  margin-bottom: 0.75rem;
  list-style-position: outside;
}

#markdown-preview ul {
  list-style-type: disc;
}

#markdown-preview ul ul {
  list-style-type: circle;
}

#markdown-preview ul ul ul {
  list-style-type: square;
}

#markdown-preview ol {
  list-style-type: decimal;
}

#markdown-preview ol ol {
  list-style-type: lower-alpha;
}

#markdown-preview ol ol ol {
  list-style-type: lower-roman;
}

#markdown-preview li {
  display: list-item;
  margin: 0.15rem 0;
}

#markdown-preview li::marker {
  color: var(--text-bright);
}

#markdown-preview li > ul,
#markdown-preview li > ol {
  margin-top: 0.25rem;
  margin-bottom: 0.25rem;
}

#markdown-preview a {
  color: var(--link);
  text-decoration: underline;
  text-underline-offset: 2px;
  text-decoration-thickness: 1px;
}

#markdown-preview a:hover {
  color: var(--link-hover);
}

#markdown-preview code {
  font-family:
    ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
  font-size: 0.9em;
  padding: 0.1rem 0.25rem;
  border-radius: 0.25rem;
  border: 1px solid var(--border-subtle);
  background-color: var(--inline-code-bg);
  color: var(--text-bright);
}

#markdown-preview pre {
  padding: 0.75rem 0.9rem;
  border-radius: 0.5rem;
  overflow-x: auto;
  margin: 0.75rem 0;
  border: 1px solid var(--border-subtle);
  background-color: var(--code-bg);
}

#markdown-preview pre code {
  display: block;
  min-width: max-content;
  background: transparent;
  padding: 0;
  border: 0;
  font-size: 0.9rem;
}

#markdown-preview .hljs {
  background: transparent;
  color: inherit;
  text-shadow: none;
}

#markdown-preview table {
  border-collapse: collapse;
  margin: 0.75rem 0;
  width: 100%;
  max-width: 100%;
}

#markdown-preview th,
#markdown-preview td {
  border: 1px solid var(--table-border);
  padding: 0.35rem 0.5rem;
  text-align: left;
  vertical-align: top;
}

#markdown-preview th {
  font-weight: 600;
  background-color: rgba(255, 255, 255, 0.04);
}

#markdown-preview blockquote {
  border-left: 4px solid #3b434b;
  padding-left: 0.75rem;
  color: var(--text-muted);
  margin: 0.75rem 0;
}

#markdown-preview hr {
  border: 0;
  border-top: 1px solid var(--hr-border);
  margin: 1rem 0;
}

#markdown-preview img {
  max-width: 100%;
  height: auto;
  border-radius: 0.375rem;
}

/* Tablet layout */

@media (max-width: 900px) {
  .viewer-layout {
    grid-template-columns: minmax(0, 1fr);
    height: auto;
  }

  .panel {
    height: clamp(320px, 60vh, 680px);
  }
}

/* Tablet toolbar layout */

@media (min-width: 701px) and (max-width: 1100px) {
  .toolbar {
    row-gap: 0.65rem;
  }

  .toolbar-spacer {
    display: none;
  }

  .toolbar-group-actions {
    display: flex;
    flex: 1 0 100%;
    order: 20;
    justify-content: flex-start;
    width: 100%;
  }

  .toolbar-group-actions .toolbar-buttons {
    display: flex;
    flex-wrap: nowrap;
    justify-content: flex-start;
    gap: 0.4rem;
    width: 100%;
  }

  .toolbar-group-actions .toolbar-group-label {
    display: none;
  }

  .toolbar-group-actions .top-btn {
    flex: 0 0 auto;
  }
}

/* Mobile layout */

@media (max-width: 700px) {
  body {
    min-height: 100dvh;
  }

  .page {
    min-height: 100dvh;
  }

  /* .container {
    padding: 1rem 0.75rem 1.25rem;
  } */

  .header-row {
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1.5rem;
  }

  .toolbox-title {
    margin: 0;
    font-size: 1.9rem;
    font-weight: 500;
    color: #d5d5d5;
    position: relative;
    padding-bottom: 0.25rem;
  }

  .header-return {
    width: 100%;
    font-size: 0.9rem;
    white-space: normal;
  }

  .intro {
    font-size: 0.86rem;
    margin-bottom: 1rem;
  }

  .toolbar-shell {
    position: static;
    top: 0;
    z-index: 20;
    margin-left: -0.75rem;
    margin-right: -0.75rem;
    margin-bottom: 1rem;
    padding: 0.0rem 0.75rem 0.75rem;
    background-color: var(--bg);
    overflow-x: hidden;
  }

  .toolbar {
    position: static;
    z-index: auto;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
    width: min(100%, 480px);
    max-width: 100%;
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 0;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.65rem 0.75rem 0.75rem;
    overflow: visible;
    background-color: var(--panel);
    box-shadow: 0 8px 18px rgba(0, 0, 0, 0.18);
  }

  .toolbar-label-desktop {
    display: none;
  }

  .toolbar-group {
    display: block;
    width: 100%;
    min-width: 0;
  }

  .toolbar-group-label {
    display: block;
    margin-bottom: 0.35rem;
    font-size: 0.68rem;
    line-height: 1;
    letter-spacing: 0.09em;
    text-transform: uppercase;
  }

  .toolbar-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    width: 100%;
    min-width: 0;
  }

  .toolbar-spacer {
    display: none;
  }

  .toolbar-group-format {
    order: 1;
  }

  .toolbar-group-blocks {
    order: 2;
  }

  .toolbar-group-actions {
    order: 3;
  }

  .toolbar-group-format .md-btn,
  .toolbar-group-blocks .md-btn {
    flex: 1 1 calc(50% - 0.4rem);
    min-width: 0;
    min-height: 2.15rem;
    padding: 0.4rem 0.65rem;
  }

  .toolbar-group-actions .toolbar-buttons {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .toolbar-group-actions .top-btn {
    width: 100%;
    min-width: 0;
    min-height: 2.25rem;
    padding-left: 0.5rem;
    padding-right: 0.5rem;
    line-height: 1.15;
    white-space: normal;
    overflow-wrap: anywhere;
  }

  .mobile-view-card {
    display: block;
    width: min(100%, 480px);
    max-width: 100%;
    margin: 0.5rem auto 0;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.65rem 0.75rem 0.75rem;
    background-color: var(--panel);
    box-shadow: 0 8px 18px rgba(0, 0, 0, 0.18);
  }

  .mobile-view-buttons {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.5rem;
    width: 100%;
  }

  .mobile-toggle {
    width: 100%;
    min-width: 0;
    min-height: 2.9rem;
    padding: 0.6rem 0.75rem;
    font-size: 0.9rem;
    font-weight: 600;
    line-height: 1.2;
    text-align: center;
  }

  .mobile-toggle.is-active {
    border-color: var(--accent);
    color: var(--accent);
    background-color: var(--accent-bg);
  }

  .viewer-layout {
    display: block;
    height: auto;
  }

  .panel {
    height: min(62dvh, 620px);
    min-height: 360px;
  }

  .panel + .panel {
    margin-top: 1rem;
  }

  body.mobile-show-editor .panel-preview {
    display: none;
  }

  body.mobile-show-preview .panel-editor {
    display: none;
  }

  .panel-header {
    padding: 0.5rem 0.65rem;
  }

  .panel-header-meta {
    display: none;
  }

  .panel-body {
    padding: 0.65rem;
  }

.toolbar-group-actions #reset-markdown {
  order: 1;
}

.toolbar-group-actions #copy-markdown {
  order: 2;
}

.toolbar-group-actions #undo-markdown {
  order: 3;
}

  #markdown-input {
    font-size: 12px;
    line-height: 1.4;
  }

  #markdown-preview {
    font-size: 0.88rem;
    line-height: 1.55;
  }

  footer {
    font-size: 0.68rem;
    line-height: 1.4;
  }
}

/* Very small screens */

@media (max-width: 480px) {
  .toolbar-group-format .md-btn,
  .toolbar-group-blocks .md-btn {
    flex-basis: calc(50% - 0.4rem);
  }

  .toolbar-group-actions .toolbar-buttons {
    grid-template-columns: minmax(0, 1fr);
  }

  .panel {
    height: 58dvh;
    min-height: 320px;
  }
}

/* Motion preferences */

@media (prefers-reduced-motion: reduce) {
  .top-btn,
  .md-btn {
    transition: none;
  }

  .top-btn:hover,
  .md-btn:hover {
    transform: none;
  }
}