/* =====================================================================
   DESIGN TOKENS
   Two fonts only:
     --mono  → system sans    — shared across UI and content
     --serif → system sans    — same font stack for a cleaner, more consistent look
   Type scale (5 steps):
     --text-xs   0.65rem  — labels, badges, sub-titles, footer
     --text-sm   0.78rem  — nav links, table cells, secondary text
     --text-base 0.92rem  — body text, notes, callouts
     --text-lg   1.1rem   — section headings, quote text
     --text-xl   1.5rem   — page titles (hero h2, welcome)
===================================================================== */

:root {
  --bg:         #f8f8fb;
  --ink:        #1f2430;
  --muted:      #5f6b7a;
  --sidebar-bg: #3d3d52;
  --accent:     #c05a4f;
  --accent2:    #4d7ea8;
  --accent3:    #5f8f6f;
  --accent4:    #8567a8;
  --accent5:    #c27a52;
  --accent6:    #4f8f8a;
  --accent7:    #3f638e;
  --rule:       #e3e6ee;
  --mono:       -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  --serif:      -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  --sidebar-w:  300px;

  --text-xs:   0.68rem;
  --text-sm:   0.82rem;
  --text-base: 0.98rem;
  --text-lg:   1.18rem;
  --text-xl:   1.65rem;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }

body {
  display: flex;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: var(--text-base);
  line-height: 1.68;
  letter-spacing: 0.01em;
}

/* ── Sidebar ─────────────────────────────────────────────────────── */

.sidebar {
  width: var(--sidebar-w);
  height: 100vh;
  background: var(--sidebar-bg);
  border-right: 1px solid #4a4a62;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 2rem 1.4rem 1.5rem;
  position: sticky;
  top: 0;
  flex-shrink: 0;
  overflow-y: auto;
}

.sidebar__tagline {
  font-family: var(--mono);
  font-size: var(--text-xs);
  color: #6b7280;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 1.4rem;
}

.sidebar__nav a {
  text-align: left;
}

.linkedin-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #a0a8c0;
  text-decoration: none;
  font-family: var(--mono);
  font-size: var(--text-xs);
  transition: color 0.2s, border-color 0.2s, background 0.2s;
  padding: 0.4rem 0.8rem;
  border: 1px solid #4a4a62;
  border-radius: 4px;
  background: #454560;
}
.linkedin-link:hover { color: #0077b5; border-color: #0077b5; background: #454560; }
.linkedin-link svg { width: 13px; height: 13px; fill: currentColor; flex-shrink: 0; }

.sidebar__divider {
  width: 28px;
  border: none;
  border-top: 1px solid #4a4a62;
  margin: 1.5rem auto;
  flex-shrink: 0;
}

.sidebar__profile {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}

.sidebar__avatar {
  width: 56px; height: 56px;
  border-radius: 50%;
  background: #4a4a62;
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 1rem;
  font-family: var(--mono);
  font-size: var(--text-lg);
  font-weight: 600;
  color: #a0a8c0;
  flex-shrink: 0;
  cursor: pointer;
  transition: background 0.15s;
}
.sidebar__avatar:hover { background: #565670; }

.sidebar h1 {
  font-family: var(--mono);
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: #e8eaf6;
  margin-bottom: 0.18rem;
  cursor: pointer;
}
.sidebar h1:hover { text-decoration: underline; text-underline-offset: 3px; }

.sidebar__group { width: 100%; margin-bottom: 0.6rem; }

.sidebar__group-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #5a5f7a;
  padding: 0.3rem 0.5rem;
  border-radius: 4px;
  cursor: pointer;
  user-select: none;
  transition: background 0.15s, color 0.15s;
  margin-bottom: 0.2rem;
}
.sidebar__group-header:hover { background: #4a4a62; color: #e8eaf6; }

.sidebar__group-chevron {
  font-size: var(--text-xs);
  transition: transform 0.2s;
  color: #3d4060;
  padding: 0.2rem 0.3rem;
  border-radius: 3px;
  cursor: pointer;
}
.sidebar__group-chevron:hover { background: #565670; color: #e8eaf6; }
.sidebar__group--open .sidebar__group-chevron { transform: rotate(180deg); }
.sidebar__group--open .sidebar__group-header { color: #c8cce8; }

.sidebar__group-label {
  cursor: pointer;
  flex: 1;
  text-align: left;
  display: block;
  color: inherit;
  text-decoration: none;
}
.sidebar__group-label:hover { text-decoration: underline; text-underline-offset: 3px; }

.sidebar__nav {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.25s ease;
}
.sidebar__group--open .sidebar__nav { max-height: 5000px; }
.sidebar__nav .sidebar__group {
  margin-left: 0.35rem;
  padding-left: 0.45rem;
  border-left: 1px solid rgba(255, 255, 255, 0.12);
}

.sidebar__nav a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--mono);
  font-size: var(--text-sm);
  color: #7b82a0;
  text-decoration: none;
  padding: 0.35rem 0.6rem;
  border-radius: 4px;
  transition: background 0.15s, color 0.15s;
  margin-bottom: 0.1rem;
}
.sidebar__nav a:hover  { background: #4a4a62; color: #e8eaf6; }
.sidebar__nav a.active { background: #e8eaf6; color: #3d3d52; }

.dot { width: 6px; height: 6px; border-radius: 50%; flex-shrink: 0; }
.dot--red    { background: var(--accent); }
.dot--blue   { background: var(--accent2); }
.dot--green  { background: var(--accent3); }
.dot--purple { background: var(--accent4); }
.dot--orange { background: #e67e22; }
.dot--teal   { background: #16a085; }
.dot--gray   { background: #7f8c8d; }
.dot--burnt  { background: var(--accent5); }
.dot--cyan   { background: var(--accent6); }
.dot--navy   { background: var(--accent7); }

/* ── Main area ───────────────────────────────────────────────────── */

.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  padding: 2.25rem 2.5rem 1.5rem;
  background: #ffffff;
  min-height: 100vh;
}

.page { display: none; width: 100%; }
.page--active { display: block; }
#page-home.page--active {
  display: flex;
  flex: 1;
}

/* ── Homepage ────────────────────────────────────────────────────── */

.homepage {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: flex-start;
  flex: 1;
  min-height: 0;
  gap: 1.9rem;
  padding-top: 1rem;
}

.homepage__name {
  font-family: var(--mono);
  font-size: var(--text-xl);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.homepage__intro {
  font-family: var(--serif);
  font-size: var(--text-base);
  color: var(--muted);
  font-style: italic;
  margin-top: -1.6rem;
}

.homepage__nav {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  gap: 0.3rem;
}
.homepage__nav--bottom {
  margin-top: auto;
  padding-top: 1rem;
}
.homepage__nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--mono);
  font-size: var(--text-sm);
  color: var(--muted);
  text-decoration: none;
  padding: 0.35rem 0.6rem;
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  width: fit-content;
}
.homepage__nav-link:hover { background: var(--rule); color: var(--ink); }

.homepage__quote-wrap {
  max-width: 560px;
  border-left: 3px solid var(--rule);
  padding-left: 1.4rem;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  opacity: 0;
  animation: fadein 0.55s ease forwards;
}
@keyframes fadein {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}
.homepage__quote-text {
  font-family: var(--serif);
  font-size: 1rem;
  font-style: italic;
  font-weight: 400;
  line-height: 1.7;
  color: #5f6b7a;
}
.homepage__quote-author {
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #7a8594;
}

/* ── Section divider ─────────────────────────────────────────────── */

.section-divider {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin: 3.5rem 0 2.5rem;
}
.section-divider__line { flex: 1; border: none; border-top: 1px solid var(--rule); }
.section-divider__label {
  font-family: var(--mono);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: #bbb;
  white-space: nowrap;
}

/* ── Hero header ─────────────────────────────────────────────────── */

.main__hero {
  border-left: 2px solid var(--accent);
  padding-left: 0.9rem;
  margin-bottom: 1.5rem;
  background: transparent;
}
.main__hero.purple { border-left-color: var(--accent4); }
.main__hero.burnt  { border-left-color: var(--accent5); }
.main__hero.cyan   { border-left-color: var(--accent6); }
.main__hero.navy   { border-left-color: var(--accent7); }

.main__hero h2 {
  font-family: var(--mono);
  font-size: clamp(1.28rem, 2.4vw, 1.75rem);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.25;
}
.main__hero p {
  font-family: var(--serif);
  font-style: italic;
  color: #737983;
  font-size: var(--text-sm);
  line-height: 1.55;
  margin-top: 0.28rem;
}
.main__hero a {
  color: #5c6a78;
  text-decoration: none;
  font-style: normal;
  font-family: var(--mono);
  font-size: var(--text-xs);
  border-bottom: 1px solid #d7dcdf;
}
.main__hero a:hover { color: #31485f; }

/* ── Badges ──────────────────────────────────────────────────────── */

.badge-row { display: flex; flex-wrap: wrap; gap: 0.35rem; margin-bottom: 1.5rem; }
.badge {
  font-family: var(--mono);
  font-size: var(--text-xs);
  background: #fff4ee;
  color: #965040;
  border: 1px solid #f0cbbb;
  border-radius: 999px;
  padding: 0.15rem 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.badge.purple { background: #f5effd; color: #6f56a0; border-color: #d8c7f2; }
.badge.burnt  { background: #fff1e8; color: #a8643f; border-color: #efc6ad; }
.badge.cyan   { background: #eaf8f6; color: #3f7d79; border-color: #b8e3dc; }
.badge.navy   { background: #eef4ff; color: #45678f; border-color: #c6d9f5; }

/* ── Topic cards ─────────────────────────────────────────────────── */

.topic {
  border: none;
  border-radius: 0;
  margin-bottom: 1.5rem;
  overflow: visible;
  background: transparent;
  box-shadow: none;
  transition: none;
}
.topic:hover {
  box-shadow: none;
  transform: none;
}

.topic__header {
  display: flex; align-items: center; gap: 0.8rem;
  padding: 0.2rem 0 0.65rem; cursor: pointer; user-select: none;
  border-bottom: 1px solid #ebe5db; transition: color 0.15s;
  background: transparent;
}
.topic__header:hover { color: #2d3440; }
.topic--open .topic__header { border-bottom-color: #ddd7ce; }

.topic__num {
  font-family: var(--mono); font-size: var(--text-xs); font-weight: 600;
  color: #ffffff; background: #444444; border-radius: 50%;
  width: 1.5rem; height: 1.5rem;
  display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.topic--blue   .topic__num { background: var(--accent2); }
.topic--green  .topic__num { background: var(--accent3); }
.topic--purple .topic__num { background: var(--accent4); }
.topic--orange .topic__num { background: #d9853b; }
.topic--teal   .topic__num { background: #3b8a84; }
.topic--gray   .topic__num { background: #7f8c8d; }
.topic--burnt  .topic__num { background: var(--accent5); }
.topic--cyan   .topic__num { background: var(--accent6); }
.topic--navy   .topic__num { background: var(--accent7); }

.topic__title {
  font-family: var(--mono);
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.35;
  flex: 1;
}
.topic__chevron { font-size: var(--text-xs); color: #9aa0aa; transition: transform 0.25s; }
.topic--open .topic__chevron { transform: rotate(180deg); }
.topic__body { display: none; padding: 0.9rem 0 0.35rem; }
.topic--open .topic__body { display: block; }

/* ── Content elements ────────────────────────────────────────────── */

.note {
  font-family: var(--serif);
  font-size: var(--text-base);
  line-height: 1.72;
  margin-bottom: 0.8rem;
}

.formula-block {
  background: transparent;
  border: none;
  border-left: 2px solid var(--accent);
  border-radius: 0;
  padding: 0.25rem 0 0.25rem 0.8rem;
  margin: 0.75rem 0;
  font-family: var(--mono);
  font-size: var(--text-sm);
  overflow-x: auto;
}
.formula-block.blue   { border-left-color: var(--accent2); }
.formula-block.green  { border-left-color: var(--accent3); }
.formula-block.purple { border-left-color: var(--accent4); }
.formula-block.orange { border-left-color: #d9853b; }
.formula-block.teal   { border-left-color: #3b8a84; }
.formula-block.navy   { border-left-color: var(--accent7); }

.sub-title {
  font-family: var(--mono); font-size: var(--text-xs); text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--accent); margin: 1.15rem 0 0.32rem; font-weight: 600;
}
.sub-title.blue   { color: var(--accent2); }
.sub-title.green  { color: var(--accent3); }
.sub-title.purple { color: var(--accent4); }
.sub-title.orange { color: #d9853b; }
.sub-title.teal   { color: #3b8a84; }
.sub-title.navy   { color: var(--accent7); }

ul.notes-list { padding-left: 1.1rem; font-family: var(--serif); font-size: var(--text-base); line-height: 1.7; }
ul.notes-list li { margin-bottom: 0.34rem; }
ul.notes-list li::marker { color: var(--accent); }
.topic--navy   ul.notes-list li::marker { color: var(--accent7); }
.topic--blue   ul.notes-list li::marker { color: var(--accent2); }
.topic--green  ul.notes-list li::marker { color: var(--accent3); }
.topic--orange ul.notes-list li::marker { color: #d9853b; }
.topic--teal   ul.notes-list li::marker { color: #3b8a84; }
.topic--purple ul.notes-list li::marker { color: var(--accent4); }

.callout {
  font-family: var(--serif);
  background: transparent;
  border: none;
  border-left: 2px solid #d8d2c8;
  border-radius: 0;
  padding: 0.2rem 0 0.2rem 0.8rem;
  margin: 0.75rem 0;
  font-size: var(--text-base);
  font-style: italic;
  color: #565d68;
}
.callout.purple,
.callout.navy {
  background: transparent;
  border-color: #d8d2c8;
  color: #565d68;
}

.blog-post {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.blog-header {
  padding-bottom: 0.25rem;
  border-bottom: 1px solid #f0ebf7;
}

.blog-header h1 {
  font-family: var(--mono);
  font-size: 1.08rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.4;
  margin-bottom: 0.3rem;
}

.blog-header .sub-title {
  margin: 0;
}

.blog-post > section,
.blog-post > aside {
  margin: 0.1rem 0;
}

.blog-post h2,
.blog-post h3 {
  font-family: var(--mono);
  font-style: normal;
  color: #384152;
}

.blog-post h2 {
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent4);
  margin-bottom: 0.45rem;
}

.blog-post h3 {
  font-size: var(--text-sm);
  margin-bottom: 0.3rem;
}

.blog-post .note {
  margin-bottom: 0;
}

.blog-post .note:not(p) {
  border-left: 2px solid #ebe5db;
  padding-left: 0.8rem;
}

.blog-post code {
  font-family: var(--mono);
  font-size: 0.9em;
}

.project-figure {
  margin: 0.9rem 0 1rem;
}

.project-figure img {
  display: block;
  width: 100%;
  max-width: 780px;
  border: 1px solid #e2e6ef;
  border-radius: 10px;
  background: #f6f7fa;
}

.project-figure figcaption {
  margin-top: 0.45rem;
  font-family: var(--mono);
  font-size: var(--text-xs);
  color: #7a8594;
}

table.data-table {
  border-collapse: collapse; font-family: var(--mono); font-size: var(--text-sm);
  line-height: 1.55;
  margin: 0.85rem 0; width: 100%;
}
table.data-table th {
  background: transparent;
  color: var(--ink);
  padding: 0.34rem 0.65rem;
  text-align: left;
  border-bottom: 1px solid #d8d2c8;
}
table.data-table td {
  padding: 0.3rem 0.65rem;
  border-bottom: 1px solid #ece7de;
  background: transparent;
}
table.data-table tr:last-child td { border-bottom: none; }

.deriv-step { display: flex; align-items: flex-start; gap: 0.7rem; margin-bottom: 0.4rem; }
.step-num { font-family: var(--mono); font-size: var(--text-xs); color: #aaa; padding-top: 0.15rem; flex-shrink: 0; width: 1.1rem; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 0.75rem 0; }
.two-col .col-label { font-family: var(--mono); font-size: var(--text-xs); text-transform: uppercase; letter-spacing: 0.07em; color: #aaa; margin-bottom: 0.4rem; }
@media (max-width: 860px) { .two-col { grid-template-columns: 1fr; } }

/* ── Agentic flow diagrams ────────────────────────────────────────── */

.flow-diagram {
  display: flex; align-items: flex-start; gap: 2rem;
  margin: 1rem 0; flex-wrap: wrap;
}
.flow-column {
  display: flex; flex-direction: column; align-items: center;
  gap: 0.3rem; flex: 1; min-width: 140px;
}
.flow-column .col-label {
  font-family: var(--mono); font-size: var(--text-xs); text-transform: uppercase;
  letter-spacing: 0.07em; color: #aaa; margin-bottom: 0.4rem; text-align: center;
}
.flow-box {
  font-family: var(--mono); font-size: var(--text-sm); font-weight: 600;
  color: var(--ink); border: 1.5px solid var(--ink); border-radius: 4px;
  padding: 0.3rem 0.9rem; background: #fff; min-width: 80px; text-align: center;
}
.flow-arrow { font-size: var(--text-base); color: #bbb; line-height: 1; }
.flow-annotation { font-family: var(--mono); font-size: var(--text-xs); color: var(--muted); font-style: italic; }

/* ── Footer ──────────────────────────────────────────────────────── */

.main__footer {
  margin-top: auto;
  padding-top: 0.75rem;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: var(--text-xs);
  color: #8a8f9b;
  text-align: right;
}

/* ── Responsive ──────────────────────────────────────────────────── */

@media (max-width: 680px) {
  body { flex-direction: column; }
  .sidebar {
    width: 100%; height: auto; position: static;
    flex-direction: row; flex-wrap: wrap; justify-content: space-between;
    padding: 1rem 1.2rem; border-right: none; border-bottom: 1px solid var(--rule);
    gap: 0.6rem; overflow-y: visible;
  }
  .sidebar__avatar, .sidebar__tagline, .sidebar__divider, .sidebar__group { display: none; }
  .sidebar h1 { margin-bottom: 0; font-size: var(--text-base); }
  .main { padding: 2rem 1.1rem 3rem; }
}