/* ==========================================================================
   Intro to R — course site styles
   Structure inspired by noamross.github.io/gams-in-r-course (CC BY 4.0)
   Content adapted from swcarpentry.github.io/r-novice-gapminder (CC BY 4.0)
   This site: CC BY-NC 4.0
   ========================================================================== */

:root {
  --color-bg: #fafaf8;
  --color-surface: #ffffff;
  --color-ink: #202124;
  --color-muted: #5f6368;
  --color-border: #e3e1dc;
  --color-primary: #1f6f5c;
  --color-primary-dark: #164f42;
  --color-primary-light: #e7f3ef;
  --color-accent: #c2571a;
  --color-ok: #1f7a3d;
  --color-ok-bg: #e9f6ec;
  --color-warn: #b03a2e;
  --color-warn-bg: #fbeae7;
  --color-code-bg: #1e1e1e;
  --color-code-ink: #e8e8e8;
  --max-width: 900px;
  --radius: 10px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-sans);
  line-height: 1.6;
}

img { max-width: 100%; }

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

/* ---- Top navigation --------------------------------------------------- */

.site-header {
  background: var(--color-primary-dark);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 1px 4px rgba(0,0,0,.15);
}

.nav-wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: 56px;
}

.brand {
  color: #fff;
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: .2px;
}
.brand:hover { text-decoration: none; opacity: .9; }

.nav-links {
  display: flex;
  gap: 1.25rem;
  align-items: center;
  flex-wrap: wrap;
}

.nav-links a {
  color: #dff0ea;
  font-size: .92rem;
  font-weight: 500;
}
.nav-links a:hover { color: #fff; }
.nav-links a.active { color: #fff; border-bottom: 2px solid var(--color-accent); padding-bottom: 3px; }

.nav-student {
  font-size: .82rem;
  color: #b9d8cd;
}

/* ---- Layout shells ----------------------------------------------------- */

.page {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.25rem 1.25rem 4rem;
}

.page-wide { max-width: 1100px; }

/* ---- Hero (homepage) --------------------------------------------------- */

.hero {
  background: linear-gradient(135deg, var(--color-primary-dark), var(--color-primary));
  color: #fff;
  padding: 3.5rem 1.25rem;
  text-align: center;
}
.hero h1 { font-size: 2.1rem; margin: 0 0 .5rem; }
.hero p.tagline { font-size: 1.15rem; color: #d9efe8; margin: 0 auto; max-width: 640px; }
.hero .badges { margin-top: 1.25rem; display: flex; gap: .6rem; justify-content: center; flex-wrap: wrap; }
.badge {
  display: inline-block;
  font-size: .75rem;
  padding: .3rem .6rem;
  border-radius: 999px;
  background: rgba(255,255,255,.15);
  color: #fff;
}

/* ---- Lesson list (chapter list) ---------------------------------------- */

.lesson-grid {
  display: grid;
  gap: 1rem;
  margin: 1.5rem 0;
}

.lesson-card {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.1rem 1.25rem;
  transition: box-shadow .15s, border-color .15s;
}
.lesson-card:hover {
  box-shadow: 0 4px 14px rgba(0,0,0,.06);
  border-color: var(--color-primary);
}
.lesson-card .num {
  flex: 0 0 auto;
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 50%;
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}
.lesson-card .meta { flex: 1; }
.lesson-card h3 { margin: 0 0 .2rem; font-size: 1.05rem; }
.lesson-card h3 a { color: var(--color-ink); }
.lesson-card p { margin: 0; color: var(--color-muted); font-size: .92rem; }
.lesson-card .status {
  flex: 0 0 auto;
  font-size: .75rem;
  padding: .25rem .55rem;
  border-radius: 999px;
  align-self: center;
  white-space: nowrap;
}
.status-not-started { background: #eee; color: var(--color-muted); }
.status-in-progress { background: #fff4de; color: #8a5a00; }
.status-complete { background: var(--color-ok-bg); color: var(--color-ok); }

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

.prose h2 { margin-top: 2.2rem; border-bottom: 2px solid var(--color-border); padding-bottom: .3rem; }
.prose h3 { margin-top: 1.6rem; }
.prose pre { background: var(--color-code-bg); color: var(--color-code-ink); padding: 1rem; border-radius: 8px; overflow-x: auto; }
.prose code { background: #eef1ee; padding: .12rem .35rem; border-radius: 4px; font-family: var(--font-mono); font-size: .9em; }
.prose pre code { background: none; padding: 0; }
.prose table { width: 100%; border-collapse: collapse; margin: 1rem 0; }
.prose th, .prose td { border: 1px solid var(--color-border); padding: .5rem .6rem; text-align: left; }

/* callout boxes, styled after Carpentries "questions / objectives / challenge" boxes */
.callout {
  border-radius: var(--radius);
  padding: 1rem 1.2rem;
  margin: 1.3rem 0;
  border-left: 5px solid var(--color-primary);
  background: var(--color-primary-light);
}
.callout h4 { margin: 0 0 .4rem; font-size: .95rem; text-transform: uppercase; letter-spacing: .04em; color: var(--color-primary-dark); }
.callout.callout-objectives { border-left-color: var(--color-accent); background: #fbeee3; }
.callout.callout-objectives h4 { color: var(--color-accent); }
.callout.callout-keypoints { border-left-color: #7a5cbf; background: #f1ecfa; }
.callout.callout-keypoints h4 { color: #5b3fa0; }

/* ---- Exercise widget ---------------------------------------------------- */

.exercise {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  margin: 1.75rem 0;
  overflow: hidden;
  background: var(--color-surface);
}
.exercise-head {
  background: #f4f2ec;
  padding: .8rem 1.1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
  border-bottom: 1px solid var(--color-border);
}
.exercise-head h4 { margin: 0; font-size: .95rem; }
.exercise-attempts { font-size: .78rem; color: var(--color-muted); white-space: nowrap; }
.exercise-body { padding: 1rem 1.1rem; }
.exercise-prompt { margin: 0 0 .8rem; }
.exercise-editor-wrap { position: relative; }
.exercise-editor {
  width: 100%;
  min-height: 120px;
  font-family: var(--font-mono);
  font-size: .9rem;
  background: var(--color-code-bg);
  color: var(--color-code-ink);
  border: none;
  border-radius: 8px;
  padding: .8rem;
  resize: vertical;
  tab-size: 2;
}
.exercise-editor:focus { outline: 2px solid var(--color-primary); }
.paste-flag {
  display: none;
  margin-top: .4rem;
  font-size: .8rem;
  color: var(--color-warn);
  background: var(--color-warn-bg);
  padding: .4rem .6rem;
  border-radius: 6px;
}
.exercise-controls { display: flex; gap: .6rem; margin-top: .7rem; align-items: center; flex-wrap: wrap; }
.btn {
  border: none;
  border-radius: 6px;
  padding: .5rem 1rem;
  font-size: .88rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity .15s;
}
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-run { background: #444; color: #fff; }
.btn-check { background: var(--color-primary); color: #fff; }
.btn-secondary { background: #eee; color: var(--color-ink); }
.btn:hover:not(:disabled) { opacity: .85; }
.exercise-output {
  margin-top: .8rem;
  font-family: var(--font-mono);
  font-size: .85rem;
  background: #f4f2ec;
  border-radius: 6px;
  padding: .7rem .9rem;
  white-space: pre-wrap;
  display: none;
}
.exercise-feedback {
  margin-top: .6rem;
  border-radius: 6px;
  padding: .6rem .9rem;
  font-size: .88rem;
  display: none;
}
.exercise-feedback.ok { background: var(--color-ok-bg); color: var(--color-ok); display: block; }
.exercise-feedback.warn { background: var(--color-warn-bg); color: var(--color-warn); display: block; }
.exercise-feedback.locked { background: #eee; color: var(--color-muted); display: block; }

/* ---- Lesson prev/next nav ------------------------------------------------ */

.lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}
.lesson-nav a {
  flex: 1;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: .9rem 1.1rem;
  color: var(--color-ink);
}
.lesson-nav a:hover { border-color: var(--color-primary); text-decoration: none; }
.lesson-nav .dir { display: block; font-size: .75rem; color: var(--color-muted); text-transform: uppercase; letter-spacing: .05em; }
.lesson-nav .next { text-align: right; }

/* ---- Proof-of-completion panel ------------------------------------------ */

.proof-panel {
  margin-top: 2.5rem;
  padding: 1.25rem 1.4rem;
  border: 2px dashed var(--color-primary);
  border-radius: var(--radius);
  background: var(--color-primary-light);
}
.proof-panel h3 { margin-top: 0; color: var(--color-primary-dark); }
.proof-panel .btn-pdf { background: var(--color-accent); color: #fff; }

/* ---- Student setup modal ------------------------------------------------- */

.modal-backdrop {
  position: fixed; inset: 0; background: rgba(0,0,0,.5);
  display: flex; align-items: center; justify-content: center;
  z-index: 100;
}
.modal-box {
  background: #fff; border-radius: var(--radius); padding: 1.75rem;
  max-width: 420px; width: 90%;
}
.modal-box h2 { margin-top: 0; }
.modal-box label { display: block; font-size: .85rem; margin: .8rem 0 .3rem; color: var(--color-muted); }
.modal-box input[type=text], .modal-box input[type=email] {
  width: 100%; padding: .55rem .7rem; border: 1px solid var(--color-border); border-radius: 6px; font-size: .95rem;
}
.modal-box .honor {
  margin-top: 1rem; font-size: .82rem; display: flex; gap: .5rem; align-items: flex-start; color: var(--color-muted);
}

/* ---- Footer -------------------------------------------------------------- */

.site-footer {
  background: #efece4;
  border-top: 1px solid var(--color-border);
  margin-top: 3rem;
}
.footer-wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2.5rem 1.25rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
  font-size: .88rem;
  color: var(--color-muted);
}
.footer-wrap h4 { color: var(--color-ink); margin: 0 0 .6rem; font-size: .85rem; text-transform: uppercase; letter-spacing: .04em; }
.footer-wrap p, .footer-wrap li { margin: 0 0 .4rem; }
.footer-wrap ul { list-style: none; padding: 0; }
.footer-license {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.25rem 2rem;
  font-size: .8rem;
  color: var(--color-muted);
  border-top: 1px solid var(--color-border);
  padding-top: 1.25rem;
}
.footer-license a { color: var(--color-muted); text-decoration: underline; }
.cc-badge { display: inline-flex; align-items: center; gap: .4rem; margin-top: .5rem; }
.cc-badge img { height: 22px; }

/* ---- Utility -------------------------------------------------------------- */

.text-muted { color: var(--color-muted); }
.mt-0 { margin-top: 0; }
.center { text-align: center; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); }

@media (max-width: 640px) {
  .hero h1 { font-size: 1.6rem; }
  .nav-links { display: none; }
  .lesson-nav { flex-direction: column; }
}

/* ---- Week grouping (homepage) ----------------------------------------- */
.week { margin-top: 2rem; }
.week-head { margin: 0 0 .6rem; font-size: 1.15rem; color: var(--color-primary-dark); }
.week-head span { font-weight: 400; font-size: .92rem; color: var(--color-muted); margin-left: .4rem; }
.week-note { margin: -.2rem 0 .7rem; font-size: .9rem; color: var(--color-muted); }
.lesson-card .when { font-size: .78rem; text-transform: uppercase; letter-spacing: .04em; color: var(--color-accent); margin-bottom: .15rem; }
.session-card { background: transparent; border-style: dashed; }
.session-card:hover { border-color: var(--color-border); }

/* ---- Plots drawn by Run ------------------------------------------------ */
.exercise-plots canvas { display: block; max-width: 100%; height: auto; margin-top: .6rem;
  border: 1px solid var(--color-border); border-radius: 6px; background: #fff; }