/* =====================================================================
   SQL Course — shared design system
   Used by every lesson and reference doc so the course reads as one thing.
   Aesthetic: calm, Tufte-ish, editorial. Serif prose, mono for code.
   Works in light & dark (prefers-color-scheme). Prints cleanly.
   ===================================================================== */

:root {
  --ink:        #1e1b16;
  --ink-soft:   #4a443b;
  --ink-faint:  #6f685c;
  --paper:      #fbf9f4;
  --paper-2:    #f3efe6;
  --rule:       #e2dccf;
  --rule-2:     #d3cbb8;
  --accent:     #7a1f1f;   /* deep red — links, emphasis */
  --accent-2:   #2f5d50;   /* pine green — success accents */
  --gold:       #9a6b00;
  --ok-bg:      #e7f1ea;
  --ok-fg:      #1f5138;
  --err-bg:     #f7e6e3;
  --err-fg:     #8a2a1c;
  --code-bg:    #f3efe6;
  --sel:        #f5e6c8;

  --font-serif: Georgia, "Iowan Old Style", "Palatino Linotype", "Book Antiqua", serif;
  --font-sans:  -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono:  ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;

  --measure: 42rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink:      #ece6da;
    --ink-soft: #c3bcac;
    --ink-faint:#8f887a;
    --paper:    #16140f;
    --paper-2:  #201d16;
    --rule:     #322d24;
    --rule-2:   #443d31;
    --accent:   #e2857a;
    --accent-2: #7fc4ad;
    --gold:     #d3a53a;
    --ok-bg:    #16281f;
    --ok-fg:    #7fd0a3;
    --err-bg:   #2c1a17;
    --err-fg:   #e79c8e;
    --code-bg:  #201d16;
    --sel:      #3a2f18;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: 19px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: var(--sel); }

.wrap {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 3.2rem 1.4rem 6rem;
}
.wrap.wide { max-width: 58rem; }

/* ---- Masthead / breadcrumb ---- */
.masthead {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  font-family: var(--font-sans);
  font-size: .78rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  border-bottom: 1px solid var(--rule);
  padding-bottom: .7rem;
  margin-bottom: 2.4rem;
}
.masthead a { color: var(--ink-faint); text-decoration: none; }
.masthead a:hover { color: var(--accent); }
.masthead .course-tag { font-weight: 700; color: var(--ink-soft); }

/* ---- Typography ---- */
h1, h2, h3 { font-weight: 700; line-height: 1.18; color: var(--ink); }
h1 {
  font-size: 2.35rem;
  margin: .2rem 0 .4rem;
  letter-spacing: -.01em;
}
.subtitle {
  font-family: var(--font-sans);
  font-size: 1.02rem;
  color: var(--ink-faint);
  margin: 0 0 2.2rem;
  font-style: normal;
}
h2 {
  font-size: 1.5rem;
  margin: 2.8rem 0 .8rem;
  padding-top: .4rem;
}
h2 .num {
  font-family: var(--font-mono);
  font-size: .95rem;
  color: var(--accent);
  margin-right: .5rem;
}
h3 { font-size: 1.15rem; margin: 1.8rem 0 .5rem; }

p { margin: 0 0 1.05rem; }
strong { font-weight: 700; }
em { font-style: italic; }

a { color: var(--accent); text-underline-offset: 2px; text-decoration-thickness: 1px; }
a:hover { text-decoration: none; }

ul, ol { margin: 0 0 1.1rem; padding-left: 1.4rem; }
li { margin: .3rem 0; }

hr {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 2.6rem 0;
}

small { font-size: .82em; color: var(--ink-faint); }

/* ---- Inline + block code ---- */
code {
  font-family: var(--font-mono);
  font-size: .84em;
  background: var(--code-bg);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: .08em .34em;
}
pre {
  font-family: var(--font-mono);
  font-size: .82rem;
  line-height: 1.5;
  background: var(--code-bg);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--rule-2);
  border-radius: 6px;
  padding: .9rem 1rem;
  overflow-x: auto;
  margin: 0 0 1.2rem;
}
pre code { background: none; border: none; padding: 0; font-size: 1em; }

/* keyword tint for hand-written snippets */
.kw { color: var(--accent); font-weight: 600; }

/* ---- Callouts ---- */
.callout {
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent);
  background: var(--paper-2);
  border-radius: 6px;
  padding: 1rem 1.15rem;
  margin: 1.4rem 0;
  font-size: .96rem;
}
.callout.win    { border-left-color: var(--accent-2); }
.callout.trap   { border-left-color: var(--gold); }
.callout .label {
  font-family: var(--font-sans);
  font-size: .72rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--ink-faint);
  display: block;
  margin-bottom: .35rem;
}
.callout p:last-child { margin-bottom: 0; }

/* ---- Citations ---- */
.cite {
  font-family: var(--font-sans);
  font-size: .8rem;
  color: var(--ink-faint);
}
.cite a { color: var(--ink-soft); }
sup.ref a {
  font-family: var(--font-sans);
  font-size: .68em;
  text-decoration: none;
  color: var(--accent);
  padding: 0 .1em;
}

/* ---- Primary source box ---- */
.source-box {
  font-family: var(--font-sans);
  font-size: .9rem;
  border: 1px dashed var(--rule-2);
  border-radius: 6px;
  padding: .9rem 1.1rem;
  margin: 1.6rem 0;
  background: var(--paper-2);
}
.source-box .label {
  font-size: .72rem; letter-spacing: .1em; text-transform: uppercase;
  color: var(--ink-faint); font-weight: 700; display: block; margin-bottom: .3rem;
}

/* ---- Tables (reference / data dictionary) ---- */
table.data {
  border-collapse: collapse;
  width: 100%;
  font-family: var(--font-sans);
  font-size: .82rem;
  margin: 0 0 1.4rem;
}
table.data th, table.data td {
  text-align: left;
  padding: .4rem .6rem;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}
table.data th {
  font-weight: 700;
  color: var(--ink-soft);
  border-bottom: 2px solid var(--rule-2);
}
table.data code { font-size: .92em; }

/* =====================================================================
   Interactive SQL widgets (wired by engine.js)
   ===================================================================== */

.sql-widget {
  border: 1px solid var(--rule-2);
  border-radius: 8px;
  background: var(--paper-2);
  margin: 1.5rem 0;
  overflow: hidden;
}
.sql-widget .task {
  font-family: var(--font-sans);
  font-size: .95rem;
  padding: .9rem 1.1rem .2rem;
  margin: 0;
}
.sql-widget .task .qnum {
  display: inline-block;
  font-weight: 700;
  color: var(--accent);
  margin-right: .4rem;
}
.sql-editor {
  width: 100%;
  border: none;
  border-top: 1px solid var(--rule);
  background: var(--code-bg);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: .84rem;
  line-height: 1.5;
  padding: .8rem 1rem;
  resize: vertical;
  min-height: 4.5rem;
  display: block;
  margin-top: .8rem;
  tab-size: 2;
}
.sql-editor:focus { outline: 2px solid var(--accent-2); outline-offset: -2px; }

.sql-toolbar {
  display: flex;
  align-items: center;
  gap: .5rem;
  padding: .55rem .8rem;
  border-top: 1px solid var(--rule);
  flex-wrap: wrap;
}
.btn {
  font-family: var(--font-sans);
  font-size: .82rem;
  font-weight: 600;
  border: 1px solid var(--rule-2);
  border-radius: 6px;
  padding: .35rem .8rem;
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
}
.btn:hover { border-color: var(--accent); color: var(--accent); }
.btn.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn.primary:hover { filter: brightness(1.08); color: #fff; }
.btn.ghost { background: transparent; }
.btn .kbd { opacity: .6; font-size: .9em; margin-left: .3em; }

.sql-status {
  font-family: var(--font-sans);
  font-size: .82rem;
  margin-left: auto;
  font-weight: 600;
}
.sql-status.ok  { color: var(--ok-fg); }
.sql-status.err { color: var(--err-fg); }

.sql-output { padding: 0 .8rem .3rem; }
.sql-output:empty { display: none; }

.sql-message {
  font-family: var(--font-sans);
  font-size: .86rem;
  border-radius: 6px;
  padding: .55rem .8rem;
  margin: .6rem 0;
}
.sql-message.ok  { background: var(--ok-bg);  color: var(--ok-fg); }
.sql-message.err { background: var(--err-bg); color: var(--err-fg); }

.result-scroll { overflow-x: auto; margin: .6rem 0 .9rem; }
table.result {
  border-collapse: collapse;
  font-family: var(--font-mono);
  font-size: .78rem;
  min-width: 100%;
}
table.result th, table.result td {
  border: 1px solid var(--rule);
  padding: .28rem .55rem;
  text-align: left;
  white-space: nowrap;
}
table.result th {
  background: var(--paper);
  color: var(--ink-soft);
  font-weight: 700;
  position: sticky;
  top: 0;
}
table.result td.null { color: var(--ink-faint); font-style: italic; }
table.result tr:nth-child(even) td { background: rgba(0,0,0,.02); }
.result-meta { font-family: var(--font-sans); font-size: .76rem; color: var(--ink-faint); margin: 0 0 .5rem; }

.hint-box { padding: 0 .8rem .8rem; }
.hint-box details { font-family: var(--font-sans); font-size: .86rem; }
.hint-box summary { cursor: pointer; color: var(--accent); font-weight: 600; }
.hint-box .solution pre { margin-top: .6rem; }

/* ---- Multiple choice quiz ---- */
.quiz { margin: 1.5rem 0; }
.quiz .q {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: .98rem;
  margin: 0 0 .7rem;
}
.quiz .opts { list-style: none; padding: 0; margin: 0; }
.quiz .opts li { margin: .4rem 0; }
.quiz .opt {
  display: block; width: 100%; text-align: left;
  font-family: var(--font-mono); font-size: .82rem;
  border: 1px solid var(--rule-2); border-radius: 6px;
  padding: .5rem .8rem; background: var(--paper); color: var(--ink);
  cursor: pointer;
}
.quiz .opt:hover { border-color: var(--accent); }
.quiz .opt.correct { background: var(--ok-bg); border-color: var(--ok-fg); color: var(--ok-fg); }
.quiz .opt.wrong   { background: var(--err-bg); border-color: var(--err-fg); color: var(--err-fg); }
.quiz .explain {
  font-family: var(--font-sans); font-size: .86rem; color: var(--ink-soft);
  margin-top: .6rem; padding-left: .2rem; display: none;
}
.quiz .explain.show { display: block; }

/* ---- Progress dots for exercise sets ---- */
.exset-head {
  display: flex; align-items: baseline; justify-content: space-between;
  gap: 1rem; margin: 2.4rem 0 .4rem;
}
.exset-head h2 { margin: 0; }
.progress {
  font-family: var(--font-mono); font-size: .8rem; color: var(--ink-faint);
  white-space: nowrap;
}
.progress b { color: var(--accent-2); }

/* ---- Cards (syllabus) ---- */
.cards { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr)); margin: 1.4rem 0; }
.card {
  border: 1px solid var(--rule); border-radius: 8px; padding: 1rem 1.1rem;
  background: var(--paper-2); text-decoration: none; color: var(--ink); display: block;
}
.card:hover { border-color: var(--accent); }
.card .k { font-family: var(--font-mono); font-size: .74rem; color: var(--accent); }
.card h3 { margin: .3rem 0 .3rem; font-size: 1.02rem; }
.card p { font-family: var(--font-sans); font-size: .83rem; color: var(--ink-soft); margin: 0; }
.card .meta { font-family: var(--font-sans); font-size: .74rem; color: var(--ink-faint); margin-top: .5rem; }
.card.locked { opacity: .55; }
.card.locked:hover { border-color: var(--rule); }

/* ---- Footer / ask-your-teacher ---- */
.lesson-footer {
  margin-top: 3.5rem;
  border-top: 1px solid var(--rule);
  padding-top: 1.3rem;
  font-family: var(--font-sans);
  font-size: .9rem;
  color: var(--ink-soft);
}
.lesson-footer .ask {
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent-2);
  border-radius: 6px;
  padding: .9rem 1.1rem;
  margin-bottom: 1.2rem;
}
.lesson-nav { display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.lesson-nav a { font-weight: 600; }

.boot-note {
  font-family: var(--font-sans); font-size: .8rem; color: var(--ink-faint);
  border: 1px dashed var(--rule-2); border-radius: 6px; padding: .5rem .8rem; margin: 1rem 0;
}
.boot-note.err { color: var(--err-fg); border-color: var(--err-fg); }

/* ---- Print ---- */
@media print {
  :root { --paper:#fff; --paper-2:#fff; --code-bg:#f4f4f4; }
  body { font-size: 11pt; color: #000; }
  .sql-toolbar, .btn, .masthead a, .lesson-nav { display: none; }
  .wrap { max-width: none; padding: 0; }
  pre, .callout, table.data th, table.data td { border-color: #bbb; }
  a { color: #000; text-decoration: underline; }
  .sql-widget { break-inside: avoid; }
}