/* AMOLED Black Professional Base System */
:root {
  color-scheme: dark;

  --bg-core: #000000;
  --bg-sidebar: #050505;
  --bg-card: #0a0a0c;
  --bg-card-hover: #121216;
  --bg-code-header: #14141b;
  --bg-code-body: #0d0d13;
  --bg-floating: #0a0a0d;
  --bg-modal: #08080a;

  --border-dim: #22222b;
  --border-mid: #2e2e3b;
  --border-focus: #6366f1;

  /* Professional Indigo / Cobalt Palette */
  --accent-primary: #6366f1;
  --accent-primary-hover: #4f46e5;
  --accent-secondary: #3b82f6;
  --accent-surface: rgba(99, 102, 241, 0.08);
  --accent-border: rgba(99, 102, 241, 0.28);
  --accent-success: #10b981;

  --text-main: #f4f4f5;
  --text-muted: #a1a1aa;
  --text-faint: #52525b;
  --text-link: #818cf8;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;

  --radius-sm: 5px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-pill: 9999px;

  --sidebar-w: 290px;
  --header-h: 54px;
  --transition-fast: 140ms ease;
  --transition-smooth: 220ms cubic-bezier(0.16, 1, 0.3, 1);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: var(--bg-core);
}

body {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background-color: var(--bg-core);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Crisp Clean Scrollbars */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-mid);
  border-radius: var(--radius-pill);
}
::-webkit-scrollbar-thumb:hover {
  background: #3f3f46;
}

/* Header - Fixed to Top Flow */
.app-header {
  flex-shrink: 0;
  height: var(--header-h);
  width: 100%;
  background: var(--bg-sidebar);
  border-bottom: 1.5px solid var(--border-dim);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.25rem;
  z-index: 30;
  position: relative;
}

.header-left, .header-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.brand-badge {
  background: var(--accent-primary);
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}
.brand-title {
  font-size: 0.98rem;
  color: #ffffff;
  font-weight: 600;
}

.stats-pill {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: #08080a;
  border: 1px solid var(--border-dim);
  padding: 0.3rem 0.85rem;
  border-radius: var(--radius-pill);
  font-size: 0.76rem;
  color: var(--text-muted);
}
.stat-sep {
  color: var(--text-faint);
}

/* Base Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  border: 1px solid transparent;
  cursor: pointer;
  padding: 0.45rem 0.9rem;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}
.primary-btn {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}
.primary-btn:hover {
  background: var(--accent-primary-hover);
  border-color: var(--accent-primary-hover);
}
.secondary-btn {
  background: #111116;
  color: var(--text-main);
  border-color: var(--border-mid);
}
.secondary-btn:hover {
  background: #181820;
  border-color: var(--text-muted);
}
.ghost-btn {
  background: transparent;
  color: var(--text-muted);
}
.ghost-btn:hover {
  color: var(--text-main);
  background: #111116;
}
.icon-btn {
  background: transparent;
  border: 1px solid var(--border-dim);
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.4rem;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}
.icon-btn:hover {
  color: var(--text-main);
  background: #111116;
  border-color: var(--border-mid);
}

/* Master App Layout */
.app-body {
  flex: 1;
  min-height: 0;
  width: 100%;
  display: flex;
  position: relative;
  overflow: hidden;
  background-color: var(--bg-core);
}

/* Block-level scroll container to prevent flex scroll-padding collapse */
.viewer-workspace {
  flex: 1;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 2.25rem 2rem 4rem 2rem;
  scroll-behavior: smooth;
  display: block;
  background-color: var(--bg-core);
}

.markdown-viewer {
  width: 100%;
  max-width: 840px;
  margin: 0 auto;
}

@media (max-width: 768px) {
  .header-center {
    display: none;
  }
  .viewer-workspace {
    padding: 1.25rem 1rem 3rem 1rem;
  }
}