/* ==========================================================================
   CYS401 slide-breakdown shared design layer
   Loaded AFTER each page's own <style>. Provides:
     · neutral theme tokens for light + dark (--bd-*)
     · floating control rail (theme toggle, top, print)
     · reading-progress bar
     · typography, table, code, focus, scrollbar and print polish
   Each page keeps its own accent palette and layout.
   ========================================================================== */

:root {
  --bd-bg: #f4f6fa;
  --bd-bg-alt: #eaeef6;
  --bd-surface: #ffffff;
  --bd-surface-2: #f7f9fc;
  --bd-border: #dbe2ee;
  --bd-border-soft: rgba(20, 32, 55, 0.08);
  --bd-text: #131a26;
  --bd-text-dim: #5a6779;
  --bd-shadow:
    0 1px 2px rgba(15, 25, 45, 0.05), 0 10px 30px rgba(15, 25, 45, 0.07);
  --bd-ring: rgba(56, 132, 232, 0.45);
  --bd-radius: 14px;
}

html[data-theme="dark"] {
  --bd-bg: #080c14;
  --bd-bg-alt: #0c121d;
  --bd-surface: #111926;
  --bd-surface-2: #0d141f;
  --bd-border: #22304a;
  --bd-border-soft: rgba(190, 214, 255, 0.1);
  --bd-text: #e6ecf6;
  --bd-text-dim: #93a3bb;
  --bd-shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 14px 36px rgba(0, 0, 0, 0.45);
  --bd-ring: rgba(120, 190, 255, 0.5);
}

/* ---------- typography polish (inherits each page's own fonts) ---------- */
html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}

body {
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4 {
  text-wrap: balance;
}

p,
li {
  text-wrap: pretty;
}

/* ---------- readable tables everywhere ---------- */
.bd-table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: var(--bd-radius);
  scrollbar-width: thin;
}

.bd-table-scroll > table {
  min-width: 460px;
}

/* ---------- focus + selection ---------- */
a:focus-visible,
button:focus-visible,
select:focus-visible,
input:focus-visible,
[tabindex]:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--bd-ring);
  outline-offset: 2px;
  border-radius: 6px;
}

/* ---------- scrollbar ---------- */
* {
  scrollbar-color: var(--bd-border) transparent;
}

::-webkit-scrollbar {
  width: 11px;
  height: 11px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--bd-border);
  border-radius: 999px;
  border: 3px solid transparent;
  background-clip: content-box;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--bd-text-dim);
  background-clip: content-box;
}

/* ---------- reading progress ---------- */
.bd-progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: 3px;
  z-index: 2147483000;
  background: transparent;
  pointer-events: none;
}

.bd-progress > i {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6, #ec4899);
  transition: width 0.1s linear;
}

/* ---------- floating control rail ---------- */
.bd-rail {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 2147483000;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-family: ui-monospace, "JetBrains Mono", SFMono-Regular, Menlo, monospace;
}

.bd-rail button {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bd-surface);
  color: var(--bd-text-dim);
  border: 1px solid var(--bd-border);
  box-shadow: var(--bd-shadow);
  transition:
    transform 0.18s ease,
    color 0.18s ease,
    border-color 0.18s ease,
    opacity 0.25s ease;
  padding: 0;
}

.bd-rail button:hover {
  transform: translateY(-2px);
  color: var(--bd-text);
  border-color: var(--bd-ring);
}

.bd-rail button:active {
  transform: translateY(0);
}

.bd-rail button svg {
  width: 18px;
  height: 18px;
  stroke-width: 2;
}

.bd-rail button.bd-hidden {
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
}

.bd-rail .bd-tip {
  position: absolute;
  right: 52px;
  white-space: nowrap;
  background: var(--bd-text);
  color: var(--bd-bg);
  font-size: 11px;
  padding: 5px 9px;
  border-radius: 7px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.16s ease;
}

.bd-rail button:hover .bd-tip {
  opacity: 0.95;
}

@media (max-width: 600px) {
  .bd-rail {
    right: 12px;
    bottom: 12px;
  }

  .bd-rail button {
    width: 38px;
    height: 38px;
  }

  .bd-rail .bd-tip {
    display: none;
  }
}

/* ---------- theme transition (skipped on first paint) ---------- */
html.bd-ready body,
html.bd-ready body * {
  transition:
    background-color 0.28s ease,
    border-color 0.28s ease,
    color 0.28s ease;
}

html.bd-ready body *:hover {
  transition-duration: 0.18s;
}

/* ---------- print ---------- */
@media print {
  .bd-rail,
  .bd-progress {
    display: none !important;
  }

  body {
    background: #fff !important;
    color: #000 !important;
  }

  * {
    box-shadow: none !important;
  }

  a[href^="http"]::after {
    content: " (" attr(href) ")";
    font-size: 10px;
    color: #555;
  }
}