/* ── Reset & Base ───────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --dark:    #065A82;
  --mid:     #1C7293;
  --accent:  #02C39A;
  --light:   #F0F8FC;
  --white:   #ffffff;
  --gray:    #475569;
  --lgray:   #94A3B8;
  --black:   #1E293B;
  --code-bg: #1E293B;
  --warn:    #F59E0B;
  --sidebar: 240px;
  --radius:  6px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--black);
  background: var(--white);
  display: flex;
  min-height: 100vh;
}

a { color: var(--mid); text-decoration: none; }
a:hover { color: var(--accent); text-decoration: underline; }

/* ── Sidebar ─────────────────────────────────────────────────── */
.sidebar {
  width: var(--sidebar);
  min-height: 100vh;
  background: var(--dark);
  color: var(--white);
  position: fixed;
  top: 0; left: 0;
  display: flex;
  flex-direction: column;
  padding: 0;
  z-index: 100;
}

.sidebar-logo {
  padding: 24px 20px 16px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.sidebar-logo a {
  color: var(--white);
  font-size: 15px;
  font-weight: 700;
  line-height: 1.3;
  display: block;
}
.sidebar-logo span {
  display: block;
  font-size: 11px;
  font-weight: 400;
  color: var(--lgray);
  margin-top: 4px;
}

.sidebar nav { flex: 1; padding: 12px 0; }

.nav-section {
  padding: 10px 20px 4px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 1.2px;
  color: var(--lgray);
  text-transform: uppercase;
}

.sidebar nav a {
  display: block;
  padding: 8px 20px;
  color: rgba(255,255,255,0.75);
  font-size: 14px;
  transition: background 0.15s, color 0.15s;
  border-left: 3px solid transparent;
}
.sidebar nav a:hover,
.sidebar nav a.active {
  background: rgba(255,255,255,0.08);
  color: var(--white);
  text-decoration: none;
  border-left-color: var(--accent);
}
.sidebar nav a .day-label {
  display: block;
  font-size: 10px;
  color: var(--lgray);
  margin-top: 1px;
}
.sidebar nav a.active .day-label { color: var(--accent); }

.sidebar-footer {
  padding: 16px 20px;
  border-top: 1px solid rgba(255,255,255,0.1);
  font-size: 12px;
  color: var(--lgray);
}

/* ── Main Content ────────────────────────────────────────────── */
.main {
  margin-left: var(--sidebar);
  flex: 1;
  min-height: 100vh;
}

.page-header {
  background: var(--dark);
  color: var(--white);
  padding: 40px 48px 32px;
  border-bottom: 3px solid var(--accent);
}
.page-header .day-tag {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
}
.page-header h1 { font-size: 28px; font-weight: 700; margin-bottom: 8px; }
.page-header .meta {
  font-size: 14px;
  color: var(--lgray);
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 10px;
}
.page-header .meta span::before { content: "• "; }

.content { padding: 40px 48px; max-width: 900px; }

/* ── Sections ────────────────────────────────────────────────── */
.section { margin-bottom: 48px; }

.section-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--light);
  display: flex;
  align-items: center;
  gap: 10px;
}
.section-title .badge {
  font-size: 11px;
  font-weight: 600;
  background: var(--accent);
  color: var(--white);
  padding: 2px 8px;
  border-radius: 20px;
  letter-spacing: 0.5px;
}
.section-title .badge.demo { background: var(--mid); }
.section-title .badge.ai   { background: var(--accent); }
.section-title .badge.tip  { background: var(--warn); color: var(--black); }

h2 { font-size: 18px; font-weight: 600; color: var(--dark); margin: 28px 0 10px; }
h3 { font-size: 15px; font-weight: 600; color: var(--gray); margin: 20px 0 8px; text-transform: uppercase; letter-spacing: 0.5px; }

p { margin-bottom: 12px; color: var(--gray); }
ul, ol { margin: 0 0 14px 20px; color: var(--gray); }
li { margin-bottom: 4px; }

/* ── Code Blocks ─────────────────────────────────────────────── */
.code-block {
  position: relative;
  margin: 16px 0 24px;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.code-header {
  background: #0F172A;
  padding: 8px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
}
.code-lang {
  color: var(--accent);
  font-family: "SFMono-Regular", Consolas, monospace;
  font-weight: 600;
  letter-spacing: 0.5px;
}
.copy-btn {
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.2);
  color: var(--lgray);
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 4px;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.15s, color 0.15s;
}
.copy-btn:hover { background: rgba(255,255,255,0.2); color: var(--white); }
.copy-btn.copied { background: var(--accent); color: var(--white); border-color: var(--accent); }

pre {
  background: var(--code-bg);
  padding: 20px;
  overflow-x: auto;
  margin: 0;
}
code {
  font-family: "SFMono-Regular", Consolas, "Courier New", monospace;
  font-size: 13.5px;
  line-height: 1.6;
  color: #E2E8F0;
}

/* Syntax colors */
.kw  { color: #7DD3FC; }   /* keywords / functions */
.fn  { color: #02C39A; }   /* ggplot / tidyverse verbs */
.st  { color: #FCA5A5; }   /* strings */
.cm  { color: #64748B; font-style: italic; } /* comments */
.nm  { color: #FCD34D; }   /* numbers */
.op  { color: #94A3B8; }   /* operators */

/* inline code */
p code, li code {
  background: #EFF6FF;
  color: var(--dark);
  padding: 1px 5px;
  border-radius: 3px;
  font-size: 13px;
}

/* ── Callout Boxes ───────────────────────────────────────────── */
.callout {
  border-radius: var(--radius);
  padding: 16px 20px;
  margin: 20px 0;
  border-left: 4px solid;
}
.callout p { margin: 0; }
.callout-title { font-weight: 700; font-size: 13px; margin-bottom: 6px; text-transform: uppercase; letter-spacing: 0.5px; }

.callout.demo   { background: #EFF6FF; border-color: var(--mid);    }
.callout.demo .callout-title   { color: var(--mid);    }
.callout.demo p  { color: #1E3A5F; }

.callout.ai     { background: #ECFDF5; border-color: var(--accent); }
.callout.ai .callout-title     { color: #047857;        }
.callout.ai p    { color: #064E3B; }

.callout.tip    { background: #FFFBEB; border-color: var(--warn);   }
.callout.tip .callout-title    { color: #92400E;        }
.callout.tip p   { color: #78350F; }

.callout.warn   { background: #FFF1F2; border-color: #E11D48;       }
.callout.warn .callout-title   { color: #9F1239;        }
.callout.warn p  { color: #881337; }

/* ── Prompt Box ──────────────────────────────────────────────── */
.prompt-box {
  background: #ECFDF5;
  border: 1px solid #6EE7B7;
  border-radius: var(--radius);
  padding: 20px 24px;
  margin: 20px 0;
  position: relative;
}
.prompt-box .prompt-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #047857;
  margin-bottom: 10px;
}
.prompt-box .prompt-text {
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 13px;
  color: #064E3B;
  line-height: 1.6;
  white-space: pre-wrap;
}
.prompt-copy {
  position: absolute;
  top: 12px; right: 12px;
  background: #047857;
  color: white;
  border: none;
  font-size: 11px;
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.15s;
}
.prompt-copy:hover { background: #065F46; }
.prompt-copy.copied { background: var(--dark); }

/* ── Timeline / Schedule ─────────────────────────────────────── */
.schedule-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14px;
}
.schedule-table th {
  text-align: left;
  padding: 10px 16px;
  background: var(--dark);
  color: var(--white);
  font-weight: 600;
  font-size: 13px;
}
.schedule-table td {
  padding: 10px 16px;
  border-bottom: 1px solid #E2E8F0;
  color: var(--gray);
  vertical-align: top;
}
.schedule-table tr:nth-child(even) td { background: var(--light); }
.schedule-table .time { font-weight: 600; color: var(--dark); white-space: nowrap; }
.schedule-table .who  { font-size: 12px; color: var(--lgray); }

/* ── Index Cards ─────────────────────────────────────────────── */
.day-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
  margin: 24px 0;
}
.day-card {
  border: 1px solid #E2E8F0;
  border-radius: var(--radius);
  padding: 24px;
  transition: box-shadow 0.15s, border-color 0.15s;
  display: block;
  color: inherit;
}
.day-card:hover {
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
  border-color: var(--accent);
  text-decoration: none;
}
.day-card .card-day {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}
.day-card h3 {
  font-size: 17px;
  font-weight: 700;
  color: var(--dark);
  margin: 0 0 8px;
  text-transform: none;
  letter-spacing: 0;
}
.day-card p { font-size: 13px; color: var(--gray); margin: 0; }
.day-card .card-date {
  font-size: 12px;
  color: var(--lgray);
  margin-top: 12px;
}

/* ── Links list ──────────────────────────────────────────────── */
.link-list { list-style: none; margin: 0 0 20px; padding: 0; }
.link-list li { padding: 6px 0; border-bottom: 1px solid #F1F5F9; }
.link-list li:last-child { border-bottom: none; }
.link-list a { font-weight: 500; }
.link-list .link-desc { display: block; font-size: 13px; color: var(--lgray); }

/* ── Page nav ────────────────────────────────────────────────── */
.page-nav {
  display: flex;
  justify-content: space-between;
  padding: 32px 0 16px;
  border-top: 1px solid #E2E8F0;
  margin-top: 48px;
  gap: 16px;
}
.page-nav a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 500;
  color: var(--mid);
}
.page-nav a:hover { color: var(--accent); text-decoration: none; }
.page-nav .next { margin-left: auto; }

/* ── Mobile ──────────────────────────────────────────────────── */
.menu-toggle {
  display: none;
  position: fixed;
  top: 12px; left: 12px;
  z-index: 200;
  background: var(--dark);
  color: white;
  border: none;
  border-radius: 4px;
  padding: 8px 12px;
  font-size: 18px;
  cursor: pointer;
}

@media (max-width: 768px) {
  .menu-toggle { display: block; }
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.25s;
  }
  .sidebar.open { transform: translateX(0); }
  .main { margin-left: 0; }
  .page-header, .content { padding: 24px 20px; }
  .page-header { padding-top: 56px; }
}