:root {
  --header-height: 56px;
  --bg: #ffffff;
  --fg: #111111;
  --muted: #666666;
  --header-bg: #000000;
  --header-fg: #ffffff;
  --border: #d9d9d9;
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

body {
  display: flex;
  flex-direction: column;
}

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--header-bg);
  color: var(--header-fg);
  display: flex;
  align-items: center;
  padding: 0 16px;
  z-index: 10;
  user-select: none;
}

.brand {
  font-weight: 700;
  letter-spacing: 0.2px;
  font-size: 17px;
  white-space: nowrap;
}

.header-right {
  margin-left: auto;
  font-size: 13px;
  opacity: 0.8;
  max-width: 55vw;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.app {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
  background: var(--bg);
}

.dropzone {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 24px;
  color: var(--muted);
  transition: background 120ms ease, color 120ms ease;
  border: 3px dashed transparent;
}

.dropzone.dragging {
  border-color: #1e90ff;
  color: #1e90ff;
  background: #f1f8ff;
}

.dropzone h1 {
  margin: 0 0 10px;
  font-size: 22px;
  font-weight: 700;
  color: var(--fg);
}

.dropzone p {
  margin: 0;
  line-height: 1.45;
}

.slide-wrap {
  position: absolute;
  inset: 0;
  padding: 24px;
  overflow: hidden;
  display: none;
}

.slide {
  width: 100%;
  height: 100%;
  margin: 0;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  overflow: auto;
  background: #ffffff;
  font-size: clamp(1.35rem, 2.2vw, 2.1rem);
  line-height: 1.45;
  -webkit-overflow-scrolling: touch;
}

.slide h1,
.slide h2,
.slide h3,
.slide h4,
.slide h5,
.slide h6 {
  margin-top: 0.25em;
  margin-bottom: 0.45em;
  line-height: 1.15;
}

.slide h1 {
  font-size: 1.9em;
}

.slide h2 {
  font-size: 1.55em;
}

.slide h3 {
  font-size: 1.3em;
}

.slide p,
.slide ul,
.slide ol,
.slide blockquote,
.slide pre,
.slide table {
  margin-top: 0.55em;
  margin-bottom: 0.55em;
}

.slide pre {
  position: relative;
  padding: 12px;
  padding-top: 44px;
  border-radius: 6px;
  border: 1px solid var(--border);
  overflow: auto;
  background: #f8f8f8;
}

.slide .mermaid-block {
  position: relative;
  margin-top: 0.55em;
  margin-bottom: 0.55em;
  padding: 12px;
  padding-top: 44px;
  border-radius: 6px;
  border: 1px solid var(--border);
  overflow: auto;
  background: #f8f8f8;
}

.slide .mermaid-graph svg {
  display: block;
  max-width: 100%;
  height: auto;
}

.slide .copy-code-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  border: 1px solid #c9c9c9;
  background: #ffffff;
  color: #222;
  border-radius: 6px;
  padding: 5px 10px;
  font-size: 0.45em;
  line-height: 1.1;
  cursor: pointer;
}

.slide .copy-code-btn:disabled {
  opacity: 0.85;
  cursor: default;
}

.slide code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  font-size: 0.9em;
}

.slide blockquote {
  border-left: 3px solid #999;
  margin-left: 0;
  padding-left: 12px;
  color: #333;
}

.slide table {
  border-collapse: collapse;
}

.slide th,
.slide td {
  border: 1px solid var(--border);
  padding: 8px 10px;
}

.slide img {
  max-width: 100%;
  height: auto;
}

.pager {
  position: absolute;
  right: 30px;
  bottom: 18px;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(0, 0, 0, 0.78);
  color: #fff;
  font-size: 12px;
  letter-spacing: 0.2px;
  display: none;
  user-select: none;
}

@media (orientation: portrait) {
  .dropzone::after {
    content: "Tip: rotate to landscape for slide-like view.";
    position: absolute;
    bottom: 22px;
    left: 16px;
    right: 16px;
    font-size: 12px;
    color: var(--muted);
  }
}