:root {
  --ink: #16233f;
  --ink-soft: #364871;
  --navy-900: #0f1b33;
  --navy-800: #16233f;
  --navy-700: #1f2f52;
  --amber: #e8a33d;
  --amber-soft: #f3c983;
  --teal: #4fa69c;
  --paper: #fdfcf8;
  --paper-line: #e4dfd2;
  --white: #ffffff;
  --radius: 10px;
  --header-h: 64px;
  --footer-h: 40px;
  --menu-w: 300px;

  --font-display: "Fraunces", "Iowan Old Style", serif;
  --font-body: "IBM Plex Sans", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }

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

body {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--navy-900);
  display: flex;
  flex-direction: column;
}

button {
  font-family: inherit;
  cursor: pointer;
}

/* ------------------------------------------------------------- header */

.app-header {
  height: var(--header-h);
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 0 20px;
  background: var(--navy-900);
  border-bottom: 1px solid var(--navy-700);
}

.menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--navy-700);
  color: var(--amber-soft);
  border-radius: 8px;
  width: 38px;
  height: 38px;
  font-size: 18px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-mark {
  width: 38px;
  height: 38px;
  border-radius: 8px;   /* 0 = square corners, 19px = perfect circle */
  object-fit: cover;
  background: var(--amber);
  flex: 0 0 auto;
}

.brand h1 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 20px;
  color: var(--white);
  margin: 0;
  letter-spacing: 0.2px;
}

/* --------------------------------------------------------------- body */

.app-body {
  flex: 1 1 auto;
  display: flex;
  min-height: 0;
}

.menu-scrim {
  display: none;
}

/* --------------------------------------------------------------- menu */

.app-menu {
  width: var(--menu-w);
  flex: 0 0 auto;
  background: var(--navy-900);
  border-right: 1px solid var(--navy-700);
  overflow-y: auto;
  padding: 18px 12px 40px;
}

.menu-grade + .menu-grade {
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid var(--navy-700);
}

.menu-grade-header {
  width: 100%;
  background: transparent;
  border: none;
  color: var(--amber-soft);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 8px;
  border-radius: 8px;
}

.menu-grade-header:hover { background: var(--navy-700); }

.menu-grade-header .chevron {
  transition: transform 0.15s ease;
  color: var(--ink-soft);
}

.menu-grade.collapsed .chevron { transform: rotate(-90deg); }
.menu-grade.collapsed .menu-topic-list { display: none; }

.menu-topic-list {
  margin-top: 4px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.menu-topic-header {
  width: 100%;
  background: transparent;
  border: none;
  color: #cdd7ec;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 8px 8px 16px;
  border-radius: 8px;
  text-align: left;
  font-size: 13.5px;
}

.menu-topic-header:hover { background: var(--navy-700); }

.topic-num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--teal);
  background: rgba(79, 166, 156, 0.12);
  border-radius: 5px;
  padding: 2px 6px;
  flex: 0 0 auto;
}

.topic-title { line-height: 1.3; }

.menu-section-list {
  display: none;
  padding: 2px 0 8px 24px;
  border-left: 1px dashed var(--navy-700);
  margin-left: 20px;
}

.menu-topic.open .menu-section-list { display: block; }

.menu-section {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: var(--ink-soft);
  padding: 10px 6px 4px;
}

.section-icon { font-size: 12px; }

.menu-file-list {
  display: flex;
  flex-direction: column;
  gap: 1px;
}

.menu-file {
  text-align: left;
  background: transparent;
  border: none;
  color: #b9c4dd;
  font-size: 13px;
  padding: 7px 10px;
  border-radius: 7px;
}

.menu-file:hover { background: var(--navy-700); color: var(--white); }

.menu-file.active {
  background: var(--amber);
  color: var(--navy-900);
  font-weight: 600;
}

/* ------------------------------------------------------------ content */

.app-content {
  flex: 1 1 auto;
  min-width: 0;
  display: flex;
  flex-direction: column;
  background: var(--paper);
  background-image:
    linear-gradient(var(--paper-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--paper-line) 1px, transparent 1px);
  background-size: 28px 28px;
}

.content-toolbar {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 22px;
  background: rgba(253, 252, 248, 0.9);
  border-bottom: 1px solid var(--paper-line);
  backdrop-filter: blur(4px);
  flex-wrap: wrap;
}

.breadcrumb {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 17px;
  color: var(--ink);
  margin: 0;
}

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

.permalink-box {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-soft);
  background: var(--white);
  border: 1px solid var(--paper-line);
  border-radius: 7px;
  padding: 6px 10px;
  max-width: 320px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.open-full-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--navy-900);
  color: var(--white);
  border: none;
  border-radius: 8px;
  padding: 9px 14px;
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
}

.open-full-btn:hover { background: var(--navy-700); }
.open-full-btn:disabled { opacity: 0.4; cursor: not-allowed; }

.content-frame-wrap {
  flex: 1 1 auto;
  min-height: 0;
  position: relative;
  padding: 18px;
}

#content-frame {
  width: 100%;
  height: 100%;
  border: 1px solid var(--paper-line);
  border-radius: var(--radius);
  background: var(--white);
  box-shadow: 0 2px 14px rgba(22, 35, 63, 0.06);
}

.content-empty {
  position: absolute;
  inset: 18px;
  display: none;
  align-items: center;
  justify-content: center;
  text-align: center;
  border: 1px dashed var(--paper-line);
  border-radius: var(--radius);
  color: var(--ink-soft);
  font-size: 15px;
  padding: 40px;
}

/* --------------------------------------------------------------footer */

.app-footer {
  flex: 0 0 auto;
  height: var(--footer-h);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 12px;
  color: var(--ink-soft);
  background: var(--navy-900);
  border-top: 1px solid var(--navy-700);
}

.app-footer span:first-child { color: var(--amber-soft); font-weight: 500; }
.footer-dot { opacity: 0.5; }

/* -------------------------------------------------------- responsive */

@media (max-width: 860px) {
  .app-menu {
    position: fixed;
    top: var(--header-h);
    bottom: 0;
    left: 0;
    z-index: 20;
    transform: translateX(-100%);
    transition: transform 0.2s ease;
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.25);
  }

  body.menu-open .app-menu { transform: translateX(0); }

  body.menu-open .menu-scrim {
    display: block;
    position: fixed;
    inset: var(--header-h) 0 0 0;
    background: rgba(15, 27, 51, 0.5);
    z-index: 15;
  }

  .menu-toggle { display: flex; align-items: center; justify-content: center; }

  .permalink-box { display: none; }
}