/* =========================================================
   DataLearn — Main Stylesheet
   Dark theme, GitHub-inspired color system
   ========================================================= */

/* ── CSS Custom Properties ── */
:root {
  --bg-0:  #090d14;
  --bg-1:  #0d1117;
  --bg-2:  #161b22;
  --bg-3:  #21262d;
  --bg-4:  #2d333b;
  --bg-hover: #30363d;

  --border-1: #21262d;
  --border-2: #30363d;
  --border-3: #444c56;

  --text-1: #e6edf3;
  --text-2: #adbac7;
  --text-3: #768390;
  --text-4: #3d444d;

  /* Language accent colors */
  --sql-clr:    #f89820;
  --sql-bg:     rgba(248,152,32,.12);
  --sql-border: rgba(248,152,32,.35);
  --py-clr:     #4b9cd3;
  --py-bg:      rgba(75,156,211,.12);
  --py-border:  rgba(75,156,211,.35);
  --sas-clr:    #7b7de8;
  --sas-bg:     rgba(123,125,232,.12);
  --sas-border: rgba(123,125,232,.35);
  --r-clr:      #2ab5a0;
  --r-bg:       rgba(42,181,160,.12);
  --r-border:   rgba(42,181,160,.35);
  --excel-clr:  #1d6f42;
  --excel-bg:   rgba(29,111,66,.12);
  --excel-border: rgba(29,111,66,.35);
  --dbt-clr:    #FF694A;
  --dbt-bg:     rgba(255,105,74,.12);
  --dbt-border: rgba(255,105,74,.35);

  /* Level colors */
  --basic-clr:  #3fb950;
  --inter-clr:  #f0883e;
  --adv-clr:    #f85149;

  /* UI tokens */
  --blue:   #539bf5;
  --green:  #3fb950;
  --orange: #f0883e;
  --red:    #f85149;
  --purple: #986ee2;
  --teal:   #2fb87a;

  --header-h: 60px;
  --sidebar-w: 220px;

  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 16px;
  --r-xl: 22px;

  --shadow-sm: 0 1px 3px rgba(0,0,0,.5);
  --shadow-md: 0 4px 14px rgba(0,0,0,.5);
  --shadow-lg: 0 10px 40px rgba(0,0,0,.55);

  --transition: .2s ease;

  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg-1);
  color: var(--text-1);
  overflow-x: hidden;
  overflow-y: auto;
  min-height: 100vh;
  line-height: 1.6;
}
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
ul { list-style: none; }
button { cursor: pointer; border: none; outline: none; background: none; font-family: var(--font); }
input { font-family: var(--font); }
code, pre { font-family: var(--mono); }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-1); }
::-webkit-scrollbar-thumb { background: var(--bg-4); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-3); }

/* =========================================================
   HEADER
   ========================================================= */
/* Override inline sticky on the fundraiser banner so it scrolls away
   and doesn't compete with the sticky app-header below it */
.fundraiser-banner { position: relative !important; }

#app {
  display: flex;
  flex-direction: column;
}

.app-header {
  position: sticky; top: 0; z-index: 300;
  flex-shrink: 0;
  height: var(--header-h);
  background: var(--bg-2);
  border-bottom: 1px solid var(--border-1);
  display: flex; align-items: center; gap: 16px; padding: 0 16px;
  box-shadow: var(--shadow-sm);
}

.header-brand { display: flex; align-items: center; gap: 10px; min-width: 200px; }

.menu-toggle {
  width: 36px; height: 36px;
  border-radius: var(--r-sm);
  color: var(--text-2);
  display: flex; align-items: center; justify-content: center;
  transition: var(--transition);
}
.menu-toggle:hover { background: var(--bg-3); color: var(--text-1); }

.brand-logo {
  display: flex; align-items: center; gap: 8px;
  font-size: 18px; font-weight: 800; letter-spacing: -.4px;
}
.brand-logo i {
  color: var(--sql-clr);
  font-size: 20px;
}

/* Language Nav */
.header-lang-nav {
  display: flex; align-items: center; gap: 6px;
  flex: 1; justify-content: center;
}

.lang-pill {
  display: flex; align-items: center; gap: 7px;
  padding: 7px 18px;
  border-radius: 20px;
  font-size: 14px; font-weight: 600;
  color: var(--text-2);
  background: transparent;
  border: 1px solid transparent;
  transition: var(--transition);
}
.lang-pill:hover { background: var(--bg-3); color: var(--text-1); }
.lang-pill.active[data-lang="sql"]    { background: var(--sql-bg);  color: var(--sql-clr);  border-color: var(--sql-border); }
.lang-pill.active[data-lang="python"] { background: var(--py-bg);   color: var(--py-clr);   border-color: var(--py-border); }
.lang-pill.active[data-lang="sas"]    { background: var(--sas-bg);  color: var(--sas-clr);  border-color: var(--sas-border); }
.lang-pill.active[data-lang="r"]      { background: var(--r-bg);    color: var(--r-clr);    border-color: var(--r-border); }
.lang-pill.active[data-lang="excel"]  { background: var(--excel-bg); color: var(--excel-clr); border-color: var(--excel-border); }
.lang-pill.active[data-lang="dbt"]    { background: var(--dbt-bg);   color: var(--dbt-clr);   border-color: var(--dbt-border); }

/* Header Actions */
.header-actions { display: flex; align-items: center; gap: 10px; margin-left: auto; }

.xp-display {
  display: flex; align-items: center; gap: 5px;
  font-size: 13px; font-weight: 600;
  color: #c69026;
  background: rgba(198,144,38,.12);
  border: 1px solid rgba(198,144,38,.3);
  padding: 5px 12px; border-radius: 14px;
}

.progress-capsule {
  display: flex; align-items: center; gap: 8px;
  font-size: 12px; font-weight: 500; color: var(--text-3);
  background: var(--bg-3);
  padding: 5px 10px; border-radius: 14px;
}
.mini-progress {
  width: 60px; height: 5px;
  background: var(--bg-4); border-radius: 3px; overflow: hidden;
}
.mini-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--green), var(--blue));
  border-radius: 3px;
  transition: width .4s ease;
}

.icon-btn {
  width: 34px; height: 34px;
  border-radius: var(--r-sm);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-2);
  transition: var(--transition);
  font-size: 15px;
}
.icon-btn:hover { background: var(--bg-3); color: var(--text-1); }
.icon-btn.sm { width: 28px; height: 28px; font-size: 13px; }

/* =========================================================
   APP BODY & LAYOUT
   ========================================================= */
.app-body {
  display: flex;
}

/* =========================================================
   SIDEBAR
   ========================================================= */
.sidebar {
  width: var(--sidebar-w);
  min-width: var(--sidebar-w);
  background: var(--bg-2);
  border-right: 1px solid var(--border-1);
  display: flex; flex-direction: column;
  overflow: hidden;
  position: sticky;
  top: var(--header-h);
  height: calc(100vh - var(--header-h));
  align-self: flex-start;
  transition: width var(--transition), min-width var(--transition);
}
.sidebar.collapsed { width: 0; min-width: 0; overflow: hidden; }

.sidebar-top {
  padding: 12px 12px 8px;
  border-bottom: 1px solid var(--border-1);
  flex-shrink: 0;
}

/* Level switcher */
.level-switcher {
  display: flex; gap: 4px;
  background: var(--bg-1); border-radius: var(--r-md);
  padding: 3px;
}
.level-btn {
  flex: 1;
  display: flex; align-items: center; justify-content: center; gap: 5px;
  padding: 6px 4px;
  border-radius: 7px;
  font-size: 12px; font-weight: 600;
  color: var(--text-3);
  transition: var(--transition);
}
.level-btn:hover { background: var(--bg-3); color: var(--text-2); }
.level-btn.active { background: var(--bg-3); color: var(--text-1); }
.level-btn.active[data-level="basic"]        { color: var(--basic-clr); }
.level-btn.active[data-level="intermediate"] { color: var(--inter-clr); }
.level-btn.active[data-level="advanced"]     { color: var(--adv-clr); }

.level-dot {
  width: 7px; height: 7px; border-radius: 50%;
}
.level-dot.basic        { background: var(--basic-clr); }
.level-dot.intermediate { background: var(--inter-clr); }
.level-dot.advanced     { background: var(--adv-clr); }

.level-progress-wrap {
  display: flex; align-items: center; gap: 8px; margin-top: 8px;
}
.level-progress-bar {
  flex: 1; height: 4px;
  background: var(--bg-4); border-radius: 2px; overflow: hidden;
}
.level-progress-fill {
  height: 100%; border-radius: 2px;
  background: linear-gradient(90deg, var(--green), var(--teal));
  transition: width .4s ease;
}
.level-progress-label { font-size: 11px; color: var(--text-3); white-space: nowrap; }

/* Lesson Nav List */
.lesson-nav {
  flex: 1; overflow-y: auto;
  padding: 8px 0;
}

.lesson-nav-item {
  display: flex; align-items: flex-start; gap: 8px;
  padding: 7px 10px;
  cursor: pointer;
  border-left: 3px solid transparent;
  transition: var(--transition);
}
.lesson-nav-item:hover { background: var(--bg-3); }
.lesson-nav-item.active {
  background: var(--bg-3);
  border-left-color: var(--sql-clr);
}
.lesson-nav-item.active[data-lang="python"] { border-left-color: var(--py-clr); }
.lesson-nav-item.active[data-lang="sas"]    { border-left-color: var(--sas-clr); }
.lesson-nav-item.active[data-lang="r"]      { border-left-color: var(--r-clr); }
.lesson-nav-item.active[data-lang="excel"]  { border-left-color: var(--excel-clr); }
.lesson-nav-item.active[data-lang="dbt"]    { border-left-color: var(--dbt-clr); }

.lni-status {
  width: 18px; height: 18px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 10px; font-weight: 700;
  flex-shrink: 0; margin-top: 1px;
}
.lni-status.num     { background: var(--bg-4); color: var(--text-3); }
.lni-status.current { background: var(--blue); color: #fff; }
.lni-status.done    { background: var(--green); color: #fff; }
.lni-status.done::before { content: '✓'; }

.lni-body { flex: 1; min-width: 0; }
.lni-title {
  font-size: 11.5px; font-weight: 500; color: var(--text-1);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.lni-meta { display: flex; gap: 6px; margin-top: 1px; }
.lni-duration, .lni-xp {
  font-size: 10px; color: var(--text-3);
}
.lni-xp { color: #c69026; }

/* =========================================================
   MAIN AREA
   ========================================================= */
.main-area {
  flex: 1; overflow-x: clip;
  background: var(--bg-1);
  padding: 28px 32px 48px;
}

/* =========================================================
   WELCOME VIEW
   ========================================================= */
.welcome-view { max-width: 980px; margin: 0 auto; }

.welcome-hero {
  text-align: center; padding: 40px 0 32px;
}
.welcome-badge {
  display: inline-flex; align-items: center; gap: 7px;
  background: var(--bg-3);
  border: 1px solid var(--border-2);
  padding: 5px 14px; border-radius: 20px;
  font-size: 13px; font-weight: 500; color: var(--text-2);
  margin-bottom: 20px;
}
.welcome-hero h1 {
  font-size: 42px; font-weight: 800; letter-spacing: -1px;
  line-height: 1.2; margin-bottom: 16px;
}
.hl { border-radius: 4px; padding: 0 4px; }
.hl.sql    { color: var(--sql-clr); }
.hl.python { color: var(--py-clr); }
.hl.sas    { color: var(--sas-clr); }
.hl.r      { color: var(--r-clr); }
.hl.excel  { color: var(--excel-clr); }
.hl.dbt    { color: var(--dbt-clr); }

.welcome-sub {
  font-size: 17px; color: var(--text-2); line-height: 1.7;
  max-width: 580px; margin: 0 auto 28px;
}
.welcome-stat-row {
  display: flex; justify-content: center; gap: 24px; flex-wrap: wrap;
  margin-top: 12px;
}
.welcome-stat {
  display: flex; flex-direction: column; align-items: center; gap: 2px;
  background: var(--bg-2); border: 1px solid var(--border-2);
  border-radius: var(--r-md); padding: 12px 24px;
}
.welcome-stat strong { font-size: 22px; font-weight: 800; color: var(--text-1); }
.welcome-stat span   { font-size: 12px; color: var(--text-3); }

/* Language Cards */
.lang-cards-row {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 20px;
  margin: 36px 0;
}
.lang-card {
  background: var(--bg-2);
  border: 1px solid var(--border-2);
  border-radius: var(--r-lg);
  padding: 26px 24px; display: flex; flex-direction: column; gap: 12px;
  transition: var(--transition);
}
.lang-card:hover { border-color: var(--border-3); transform: translateY(-2px); box-shadow: var(--shadow-md); }
.sql-card:hover  { border-color: var(--sql-border); }
.py-card:hover   { border-color: var(--py-border);  }
.sas-card:hover  { border-color: var(--sas-border); }
.r-card:hover      { border-color: var(--r-border); }
.excel-card:hover  { border-color: var(--excel-border); }

.lc-icon {
  width: 52px; height: 52px; border-radius: var(--r-md);
  display: flex; align-items: center; justify-content: center;
  font-size: 24px;
}
.sql-icon { background: var(--sql-bg); color: var(--sql-clr); }
.py-icon  { background: var(--py-bg);  color: var(--py-clr); }
.sas-icon { background: var(--sas-bg); color: var(--sas-clr); }
.r-icon     { background: var(--r-bg);     color: var(--r-clr); }
.excel-icon { background: var(--excel-bg);  color: var(--excel-clr); }
.dbt-icon   { background: var(--dbt-bg);    color: var(--dbt-clr); }

.lang-card h3 { font-size: 20px; font-weight: 700; }
.lang-card p  { font-size: 14px; color: var(--text-2); line-height: 1.6; flex: 1; }

.lc-meta { display: flex; gap: 6px; flex-wrap: wrap; }
.badge-basic { background: rgba(63,185,80,.15); color: var(--basic-clr); border: 1px solid rgba(63,185,80,.3); padding: 2px 10px; border-radius: 12px; font-size: 11px; font-weight: 600; }
.badge-inter { background: rgba(240,136,62,.15); color: var(--inter-clr); border: 1px solid rgba(240,136,62,.3); padding: 2px 10px; border-radius: 12px; font-size: 11px; font-weight: 600; }
.badge-adv   { background: rgba(248,81,73,.15);  color: var(--adv-clr);   border: 1px solid rgba(248,81,73,.3);  padding: 2px 10px; border-radius: 12px; font-size: 11px; font-weight: 600; }

.lc-count { font-size: 12px; color: var(--text-3); font-weight: 500; }

.btn-start {
  display: flex; align-items: center; justify-content: center; gap: 6px;
  padding: 10px 18px;
  border-radius: var(--r-md);
  font-size: 14px; font-weight: 600;
  color: #fff;
  transition: var(--transition);
  margin-top: auto;
}
.sql-card .btn-start { background: var(--sql-clr); }
.sql-card .btn-start:hover { background: #e08818; }
.py-card  .btn-start { background: var(--py-clr); }
.py-card  .btn-start:hover { background: #3a8abf; }
.sas-card .btn-start { background: var(--sas-clr); }
.sas-card .btn-start:hover { background: #6a6cd6; }
.r-card   .btn-start { background: var(--r-clr); }
.r-card   .btn-start:hover { background: #229980; }
.excel-card .btn-start { background: var(--excel-clr); }
.excel-card .btn-start:hover { background: #165e38; }
.dbt-card   .btn-start { background: var(--dbt-clr); }
.dbt-card   .btn-start:hover { background: #e5522e; }

/* How It Works */
.how-it-works { margin-top: 40px; }
.how-it-works h2 { font-size: 24px; font-weight: 700; text-align: center; margin-bottom: 24px; }
.how-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.how-step {
  background: var(--bg-2); border: 1px solid var(--border-1);
  border-radius: var(--r-lg); padding: 20px 18px;
}
.how-num {
  width: 36px; height: 36px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--purple));
  color: #fff; font-size: 16px; font-weight: 800;
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 12px;
}
.how-step h4 { font-size: 14px; font-weight: 700; margin-bottom: 6px; }
.how-step p  { font-size: 13px; color: var(--text-2); line-height: 1.6; }

/* =========================================================
   LESSON VIEW
   ========================================================= */
.lesson-view { max-width: 1020px; margin: 0 auto; display: flex; flex-direction: column; gap: 0; }

.lesson-hdr {
  margin-bottom: 16px;
}
.lesson-breadcrumb {
  font-size: 12px; color: var(--text-3); font-weight: 500;
  margin-bottom: 6px; text-transform: uppercase; letter-spacing: .5px;
}
.lesson-title-row {
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
}
.lesson-title { font-size: 26px; font-weight: 800; letter-spacing: -.4px; }
.lesson-meta-row { display: flex; align-items: center; gap: 8px; }
.lm-badge {
  display: flex; align-items: center; gap: 5px;
  font-size: 12px; font-weight: 500; color: var(--text-3);
  background: var(--bg-3); border-radius: 14px; padding: 4px 12px;
}
.xp-badge { color: #c69026; }

.btn-complete {
  display: flex; align-items: center; gap: 6px;
  padding: 7px 16px;
  border-radius: var(--r-md);
  font-size: 13px; font-weight: 600;
  color: var(--green);
  background: rgba(63,185,80,.1);
  border: 1px solid rgba(63,185,80,.3);
  transition: var(--transition);
}
.btn-complete:hover { background: rgba(63,185,80,.2); }
.btn-complete.completed { background: var(--green); color: #fff; border-color: var(--green); }

/* Tab Bar */
.tab-bar {
  display: flex; gap: 0;
  border-bottom: 1px solid var(--border-2);
  margin-bottom: 24px;
}
.tab-btn {
  display: flex; align-items: center; gap: 7px;
  padding: 10px 20px;
  font-size: 14px; font-weight: 600;
  color: var(--text-3);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: var(--transition);
}
.tab-btn:hover { color: var(--text-1); }
.tab-btn.active { color: var(--text-1); border-bottom-color: var(--blue); }

/* ── Section Card ── */
.section-card {
  background: var(--bg-2);
  border: 1px solid var(--border-1);
  border-radius: var(--r-lg);
  padding: 22px 24px;
  margin-bottom: 20px;
}
.section-title {
  font-size: 15px; font-weight: 700;
  color: var(--text-1); margin-bottom: 14px;
  display: flex; align-items: center; gap: 8px;
}
.section-title i { color: var(--blue); }

/* Scenario Card */
.scenario-card {
  background: linear-gradient(135deg, var(--bg-2) 0%, var(--bg-3) 100%);
  border: 1px solid var(--border-2);
  border-radius: var(--r-lg);
  padding: 22px 24px;
  margin-bottom: 20px;
  position: relative; overflow: hidden;
}
.scenario-card::before {
  content: '';
  position: absolute; left: 0; top: 0; bottom: 0; width: 4px;
  background: linear-gradient(to bottom, var(--sql-clr), var(--orange));
}
.sc-eyebrow {
  display: flex; align-items: center; gap: 8px;
  font-size: 12px; font-weight: 600; color: var(--text-3);
  text-transform: uppercase; letter-spacing: .5px;
  margin-bottom: 12px;
}
.sc-eyebrow i { color: var(--orange); }
.sc-at { color: var(--text-4); }
#scRole    { color: var(--blue); }
#scCompany { color: var(--orange); }
.sc-body { font-size: 15px; color: var(--text-2); line-height: 1.75; }

/* Objectives */
.objectives-list { padding: 0; }
.objectives-list li {
  display: flex; align-items: flex-start; gap: 10px;
  font-size: 14px; color: var(--text-2);
  padding: 5px 0;
}
.objectives-list li::before {
  content: '';
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--blue); margin-top: 5px; flex-shrink: 0;
}

/* Terminology */
.term-hint { font-size: 12px; color: var(--text-3); margin-bottom: 12px; }
.term-pills { display: flex; flex-wrap: wrap; gap: 8px; }
.term-pill {
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 13px; font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  background: var(--bg-3);
  border: 1px solid var(--border-2);
  color: var(--text-2);
}
.term-pill:hover { background: var(--bg-4); color: var(--text-1); border-color: var(--blue); }
.term-pill[data-lang="sql"]:hover    { border-color: var(--sql-clr); color: var(--sql-clr); }
.term-pill[data-lang="python"]:hover { border-color: var(--py-clr);  color: var(--py-clr); }
.term-pill[data-lang="sas"]:hover    { border-color: var(--sas-clr); color: var(--sas-clr); }

/* Theory */
.theory-body { font-size: 14px; color: var(--text-2); line-height: 1.8; }
.theory-body h3 { font-size: 16px; font-weight: 700; color: var(--text-1); margin: 20px 0 10px; }
.theory-body h3:first-child { margin-top: 0; }
.theory-body p  { margin-bottom: 12px; }
.theory-body ul, .theory-body ol { margin: 0 0 12px 20px; }
.theory-body li { margin-bottom: 6px; }
.theory-body code {
  background: var(--bg-3); border: 1px solid var(--border-2);
  border-radius: 4px; padding: 1px 6px;
  font-size: 13px; color: var(--orange);
}
.theory-body strong { color: var(--text-1); }

/* Callouts */
.callout {
  display: flex; gap: 12px; align-items: flex-start;
  border-radius: var(--r-md);
  padding: 14px 16px; margin: 14px 0;
  font-size: 13px; line-height: 1.6;
}
.callout i { font-size: 16px; flex-shrink: 0; margin-top: 1px; }
.callout-tip     { background: rgba(63,185,80,.1); border: 1px solid rgba(63,185,80,.25); }
.callout-tip i   { color: var(--green); }
.callout-warning { background: rgba(240,136,62,.1); border: 1px solid rgba(240,136,62,.25); }
.callout-warning i { color: var(--orange); }
.callout-info    { background: rgba(83,155,245,.1); border: 1px solid rgba(83,155,245,.25); }
.callout-info i  { color: var(--blue); }

/* Walkthrough */
.walkthrough-card { }
.wt-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 14px;
}
.step-nav { display: flex; align-items: center; gap: 10px; }
.step-nav-btn {
  display: flex; align-items: center; gap: 5px;
  padding: 6px 14px;
  border-radius: var(--r-md);
  font-size: 13px; font-weight: 600;
  background: var(--bg-3);
  color: var(--text-2);
  border: 1px solid var(--border-2);
  transition: var(--transition);
}
.step-nav-btn:hover:not(:disabled) { background: var(--bg-4); color: var(--text-1); }
.step-nav-btn:disabled { opacity: .35; cursor: not-allowed; }
.step-counter { font-size: 13px; color: var(--text-3); font-weight: 500; }

.step-dots {
  display: flex; gap: 6px; margin-bottom: 18px;
}
.step-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--bg-4); border: 2px solid var(--border-2);
  transition: var(--transition); cursor: pointer;
}
.step-dot.done    { background: var(--green); border-color: var(--green); }
.step-dot.current { background: var(--blue);  border-color: var(--blue);  }

.step-panel { }
.step-hdr { display: flex; align-items: flex-start; gap: 12px; margin-bottom: 14px; }
.step-badge {
  padding: 3px 12px;
  border-radius: 14px;
  font-size: 12px; font-weight: 700;
  background: var(--blue); color: #fff;
  flex-shrink: 0; margin-top: 2px;
}
.step-title2 { font-size: 18px; font-weight: 700; }
.step-explanation { font-size: 14px; color: var(--text-2); line-height: 1.75; margin-bottom: 16px; }
.step-explanation code { background: var(--bg-3); border: 1px solid var(--border-2); border-radius: 4px; padding: 1px 6px; color: var(--orange); font-size: 13px; }

.step-note {
  display: flex; align-items: flex-start; gap: 8px;
  background: rgba(83,155,245,.08);
  border: 1px solid rgba(83,155,245,.2);
  border-radius: var(--r-md);
  padding: 10px 14px; margin-top: 12px;
  font-size: 13px; color: var(--text-2);
}
.step-note i { color: var(--blue); flex-shrink: 0; margin-top: 1px; }
.step-after {
  background: var(--bg-3); border-radius: var(--r-md);
  padding: 12px 14px; margin-top: 12px;
  font-size: 13px; color: var(--text-2); line-height: 1.7;
}

/* Insight Card */
.insight-card {
  display: flex; gap: 14px; align-items: flex-start;
  background: linear-gradient(135deg, rgba(83,155,245,.08), rgba(152,110,226,.08));
  border: 1px solid rgba(83,155,245,.2);
  border-radius: var(--r-lg);
  padding: 18px 20px;
  margin-bottom: 20px;
}
.insight-icon {
  width: 40px; height: 40px;
  background: rgba(83,155,245,.15);
  border-radius: var(--r-md);
  display: flex; align-items: center; justify-content: center;
  color: var(--blue); font-size: 18px; flex-shrink: 0;
}
.insight-body strong { font-size: 13px; color: var(--text-1); display: block; margin-bottom: 4px; }
.insight-body p { font-size: 14px; color: var(--text-2); line-height: 1.7; }

.learn-footer { display: flex; justify-content: flex-end; margin-bottom: 12px; }

/* =========================================================
   EDITOR BLOCK
   ========================================================= */
.editor-block {
  border-radius: var(--r-md);
  border: 1px solid var(--border-2);
  overflow: hidden;
  margin-bottom: 12px;
}
.editor-toolbar {
  display: flex; align-items: center;
  background: var(--bg-3);
  border-bottom: 1px solid var(--border-1);
  padding: 6px 10px; gap: 8px;
}
.editor-toolbar-right { margin-left: auto; display: flex; align-items: center; gap: 6px; }
.editor-badge {
  font-size: 11px; font-weight: 700;
  padding: 2px 10px; border-radius: 12px; letter-spacing: .4px;
  text-transform: uppercase;
}
/* Dynamic editor badge colors */
.editor-badge.sql    { background: var(--sql-bg); color: var(--sql-clr); border: 1px solid var(--sql-border); }
.editor-badge.python { background: var(--py-bg);  color: var(--py-clr);  border: 1px solid var(--py-border); }
.editor-badge.sas    { background: var(--sas-bg); color: var(--sas-clr); border: 1px solid var(--sas-border); }
.editor-badge.excel  { background: var(--excel-bg); color: var(--excel-clr); border: 1px solid var(--excel-border); }
.editor-badge.dbt    { background: var(--dbt-bg);   color: var(--dbt-clr);   border: 1px solid var(--dbt-border); }

.run-btn {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px;
  border-radius: var(--r-sm);
  font-size: 13px; font-weight: 600;
  background: var(--green);
  color: #fff;
  transition: var(--transition);
}
.run-btn:hover { background: #30a044; }

.btn-primary {
  display: flex; align-items: center; gap: 6px;
  padding: 9px 20px;
  border-radius: var(--r-md); font-size: 14px; font-weight: 600;
  background: var(--blue); color: #fff;
  transition: var(--transition);
}
.btn-primary:hover { background: #3d8be8; }

.btn-secondary {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px;
  border-radius: var(--r-sm); font-size: 13px; font-weight: 600;
  background: var(--bg-4); color: var(--text-2);
  border: 1px solid var(--border-2);
  transition: var(--transition);
}
.btn-secondary:hover { background: var(--bg-hover); color: var(--text-1); }
.btn-secondary.sm { padding: 5px 10px; font-size: 12px; }

.btn-danger {
  padding: 9px 20px; border-radius: var(--r-md);
  font-size: 14px; font-weight: 600;
  background: var(--red); color: #fff;
  transition: var(--transition);
}
.btn-danger:hover { background: #e03a38; }

.hint-btn {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: var(--r-sm);
  font-size: 13px; font-weight: 600;
  background: rgba(198,144,38,.12);
  color: #c69026; border: 1px solid rgba(198,144,38,.3);
  transition: var(--transition);
}
.hint-btn:hover { background: rgba(198,144,38,.2); }

.solution-btn {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: var(--r-sm);
  font-size: 13px; font-weight: 600;
  background: rgba(152,110,226,.12);
  color: var(--purple); border: 1px solid rgba(152,110,226,.3);
  transition: var(--transition);
}
.solution-btn:hover { background: rgba(152,110,226,.22); }

.copy-btn {
  display: flex; align-items: center; gap: 5px;
  padding: 5px 11px; border-radius: var(--r-sm);
  font-size: 12px; font-weight: 500;
  background: var(--bg-4); color: var(--text-3);
  border: 1px solid var(--border-2);
  transition: var(--transition);
}
.copy-btn:hover { background: var(--bg-hover); color: var(--text-1); }

/* Output Panel */
.output-panel {
  min-height: 140px; max-height: 360px;
  overflow: auto;
  background: #0d1117;
  font-family: var(--mono);
}
.output-placeholder {
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  height: 140px; gap: 8px;
  color: var(--text-4);
}
.output-placeholder i { font-size: 28px; }
.output-placeholder p { font-size: 13px; }
.output-placeholder strong { color: var(--text-3); }

/* SQL Table Output */
.sql-result-wrap { padding: 12px; overflow-x: auto; }
.sql-table {
  border-collapse: collapse;
  font-size: 13px;
  width: 100%;
  min-width: max-content;
}
.sql-table th {
  background: var(--bg-3);
  color: var(--blue);
  font-weight: 700; text-align: left;
  padding: 8px 14px;
  border-bottom: 2px solid var(--border-2);
  white-space: nowrap;
}
.sql-table td {
  padding: 7px 14px;
  color: var(--text-2);
  border-bottom: 1px solid var(--border-1);
  white-space: nowrap;
}
.sql-table tr:hover td { background: rgba(255,255,255,.02); color: var(--text-1); }
.sql-table td.num-cell { color: var(--teal); text-align: right; }
.sql-table td.null-cell { color: var(--text-4); font-style: italic; }

.sql-result-meta {
  font-size: 11px; color: var(--text-3);
  padding: 6px 12px;
  border-top: 1px solid var(--border-1);
  font-family: var(--font);
}

.sql-error {
  background: rgba(248,81,73,.08);
  border: 1px solid rgba(248,81,73,.2);
  border-radius: var(--r-md);
  padding: 14px 16px;
  color: var(--red);
  font-size: 13px; line-height: 1.6; margin: 12px;
}
.sql-error strong { display: block; margin-bottom: 4px; }

/* Simulated / Live Output (Python · Pyodide, R · WebR, SAS, dbt) */
.sim-output { padding: 0; border-radius: var(--r-md); overflow: hidden; }

.sim-header {
  display: flex; align-items: center; gap: 8px;
  padding: 7px 14px;
  background: rgba(255,255,255,.04);
  border-bottom: 1px solid var(--border-1);
  font-size: 12px; font-weight: 600;
  color: var(--text-3); letter-spacing: .02em;
  font-family: var(--font);
}

.sim-pre {
  margin: 0; padding: 14px 16px;
  font-size: 12.5px; line-height: 1.65;
  color: #adbac7; white-space: pre-wrap; word-break: break-all;
  font-family: var(--mono);
}

/* Language-coloured header accent */
.python-output .sim-header { border-left: 3px solid #3b82f6; }
.r-output      .sim-header { border-left: 3px solid #276DC3; }
.sas-output    .sim-header { border-left: 3px solid var(--orange); }
.dbt-output    .sim-header { border-left: 3px solid #FF6B35; }
.excel-output  .sim-header { border-left: 3px solid #217346; }

/* Warning / partial-error block shown after partial output */
.output-warning {
  color: #f0a05a !important;
  border-top: 1px solid rgba(240,160,90,.2);
  background: rgba(240,160,90,.05);
}
.sim-table {
  border-collapse: collapse; width: 100%; min-width: max-content;
  font-size: 13px;
}
.sim-table th { color: var(--text-3); text-align: left; padding: 4px 16px 8px 0; font-weight: 600; white-space: nowrap; border-bottom: 1px solid var(--border-2); }
.sim-table td { padding: 5px 16px 5px 0; color: var(--text-2); white-space: nowrap; border-bottom: 1px solid var(--border-1); }
.sim-table td.idx { color: var(--text-4); }
.sim-table td.num { color: var(--teal); }

.sim-text {
  font-size: 13px; color: var(--text-2);
  line-height: 1.7; white-space: pre; overflow-x: auto;
}
.sim-label {
  font-size: 11px; color: var(--text-3); margin-bottom: 8px;
  font-family: var(--font);
}

.sas-log {
  font-size: 12px; white-space: pre; color: #adbac7;
  line-height: 1.6; overflow-x: auto; padding: 14px 16px;
}
.sas-log .log-note { color: var(--blue); }
.sas-log .log-warn { color: var(--orange); }
.sas-log .log-err  { color: var(--red); }

/* =========================================================
   PRACTICE TAB
   ========================================================= */
.practice-layout {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0;
  border: 1px solid var(--border-2); border-radius: var(--r-lg);
  overflow: hidden; margin-bottom: 12px;
}
.practice-left  { border-right: 1px solid var(--border-2); display: flex; flex-direction: column; }
.practice-right { display: flex; flex-direction: column; background: var(--bg-2); }

.output-hdr {
  display: flex; align-items: center; justify-content: space-between;
  padding: 7px 12px;
  background: var(--bg-3);
  border-bottom: 1px solid var(--border-1);
  font-size: 12px; font-weight: 600; color: var(--text-3);
}
.output-timing { font-size: 11px; color: var(--text-4); }

.sandbox-notice {
  display: flex; align-items: center; gap: 8px;
  font-size: 12px; color: var(--text-3);
  background: var(--bg-2); border: 1px solid var(--border-1);
  border-radius: var(--r-md); padding: 8px 14px;
}
.sandbox-notice i { color: var(--sql-clr); }

/* =========================================================
   CHALLENGE TAB
   ========================================================= */
.challenge-card {
  background: linear-gradient(135deg, var(--bg-2), var(--bg-3));
  border: 1px solid var(--border-2);
  border-radius: var(--r-lg);
  padding: 20px 22px; margin-bottom: 20px;
}
.challenge-card-hdr { display: flex; gap: 16px; align-items: flex-start; }
.challenge-trophy {
  width: 48px; height: 48px; border-radius: var(--r-md); flex-shrink: 0;
  background: rgba(198,144,38,.15);
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; color: #c69026;
}
.challenge-desc h3 { font-size: 17px; font-weight: 700; margin-bottom: 6px; }
.challenge-desc p  { font-size: 14px; color: var(--text-2); line-height: 1.7; }

.challenge-workspace {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0;
  border: 1px solid var(--border-2); border-radius: var(--r-lg);
  overflow: hidden; margin-bottom: 16px;
}
.challenge-left  { border-right: 1px solid var(--border-2); display: flex; flex-direction: column; }
.challenge-right { display: flex; flex-direction: column; background: var(--bg-2); }

.hint-box {
  display: flex; gap: 10px; align-items: flex-start;
  background: rgba(198,144,38,.1);
  border: 1px solid rgba(198,144,38,.25);
  border-radius: var(--r-md);
  padding: 12px 16px; margin-bottom: 14px;
  font-size: 14px; color: var(--text-2);
}
.hint-box i { color: #c69026; flex-shrink: 0; margin-top: 1px; }

.solution-box {
  background: var(--bg-2); border: 1px solid var(--border-2);
  border-radius: var(--r-lg); overflow: hidden; margin-bottom: 14px;
}
.solution-box-hdr {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 16px;
  background: var(--bg-3);
  border-bottom: 1px solid var(--border-1);
  font-size: 14px; color: var(--purple);
}
.solution-pre {
  padding: 16px; font-size: 13px;
  color: var(--text-1); overflow-x: auto;
  background: var(--bg-1); line-height: 1.7;
  border-bottom: 1px solid var(--border-1);
}
.solution-expl {
  padding: 14px 16px; font-size: 13px; color: var(--text-2); line-height: 1.7;
}
.solution-expl strong { color: var(--text-1); }

.success-banner {
  display: flex; align-items: center; gap: 14px;
  background: linear-gradient(135deg, rgba(63,185,80,.12), rgba(47,184,122,.12));
  border: 1px solid rgba(63,185,80,.3);
  border-radius: var(--r-lg);
  padding: 18px 22px; margin-bottom: 14px;
}
.success-banner > i { font-size: 32px; color: var(--green); flex-shrink: 0; }
.success-banner h4  { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.success-banner p   { font-size: 13px; color: var(--text-2); }
.success-banner .btn-primary { margin-left: auto; white-space: nowrap; }

/* =========================================================
   CODEMIRROR CUSTOMISATION
   ========================================================= */
.CodeMirror {
  font-family: var(--mono) !important;
  font-size: 14px !important;
  line-height: 1.65 !important;
  height: auto !important;
  min-height: 120px;
  background: #0d1117 !important;
  color: #e6edf3 !important;
  padding: 2px 0 !important;
}
.CodeMirror-scroll  { min-height: 120px; }
.CodeMirror-lines   { padding: 8px 0 !important; }
.CodeMirror-gutters { background: #0d1117 !important; border-right: 1px solid var(--border-1) !important; }
.CodeMirror-linenumber { color: var(--text-4) !important; padding: 0 8px !important; }
.CodeMirror-cursor  { border-left: 2px solid var(--blue) !important; }
.CodeMirror-selected { background: rgba(83,155,245,.15) !important; }
/* SQL keyword coloring */
.cm-s-dracula .cm-keyword { color: #ff79c6 !important; font-weight: 600; }
.cm-s-dracula .cm-number  { color: #bd93f9 !important; }
.cm-s-dracula .cm-string  { color: #f1fa8c !important; }
.cm-s-dracula .cm-comment { color: #6272a4 !important; }
.cm-s-dracula .cm-operator { color: #ff79c6 !important; }

/* =========================================================
   MODALS & POPUPS
   ========================================================= */
.modal-backdrop {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(0,0,0,.6);
  display: flex; align-items: center; justify-content: center;
  backdrop-filter: blur(4px);
  animation: fadeIn .2s ease;
}
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

.modal-box {
  background: var(--bg-2);
  border: 1px solid var(--border-2);
  border-radius: var(--r-xl);
  box-shadow: var(--shadow-lg);
  animation: slideUp .25s ease;
  max-height: 90vh;
  display: flex; flex-direction: column;
}
@keyframes slideUp { from { transform: translateY(20px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

.modal-hdr {
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 22px;
  border-bottom: 1px solid var(--border-1);
  flex-shrink: 0;
}
.modal-hdr h2 { font-size: 18px; font-weight: 700; display: flex; align-items: center; gap: 8px; }
.modal-hdr h2 i { color: var(--blue); }
.modal-close {
  width: 30px; height: 30px; border-radius: var(--r-sm);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-3); font-size: 14px;
  transition: var(--transition);
}
.modal-close:hover { background: var(--bg-3); color: var(--text-1); }

/* Glossary Modal */
.glossary-modal { width: 680px; }
.modal-search {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border-1);
}
.modal-search i { color: var(--text-3); }
.modal-search input {
  flex: 1; background: none; border: none; outline: none;
  font-size: 14px; color: var(--text-1);
}
.modal-search input::placeholder { color: var(--text-4); }

.filter-chips { display: flex; gap: 6px; padding: 10px 20px; border-bottom: 1px solid var(--border-1); }
.chip {
  padding: 4px 14px; border-radius: 14px; font-size: 12px; font-weight: 600;
  color: var(--text-3); background: var(--bg-3); border: 1px solid var(--border-2);
  transition: var(--transition);
}
.chip:hover { background: var(--bg-4); color: var(--text-1); }
.chip.active { background: var(--blue); color: #fff; border-color: var(--blue); }

.modal-body { overflow-y: auto; padding: 12px 20px 20px; flex: 1; }
.glossary-section-title { font-size: 12px; font-weight: 700; color: var(--text-4); letter-spacing: 1px; text-transform: uppercase; padding: 10px 0 4px; }
.glossary-entry { padding: 10px 0; border-bottom: 1px solid var(--border-1); }
.glossary-entry:last-child { border-bottom: none; }
.ge-term { font-size: 14px; font-weight: 700; color: var(--text-1); margin-bottom: 4px; }
.ge-lang { font-size: 11px; font-weight: 600; padding: 1px 8px; border-radius: 10px; margin-left: 8px; }
.ge-lang.sql    { background: var(--sql-bg); color: var(--sql-clr); }
.ge-lang.python { background: var(--py-bg);  color: var(--py-clr); }
.ge-lang.sas    { background: var(--sas-bg); color: var(--sas-clr); }
.ge-def  { font-size: 13px; color: var(--text-2); line-height: 1.6; margin-bottom: 4px; }
.ge-example { font-size: 12px; font-family: var(--mono); color: var(--orange); background: var(--bg-3); padding: 4px 10px; border-radius: var(--r-sm); }

/* Term Popup */
.term-popup {
  position: fixed; z-index: 300;
  background: var(--bg-2);
  border: 1px solid var(--border-3);
  border-radius: var(--r-md);
  padding: 0;
  max-width: 320px; min-width: 220px;
  box-shadow: var(--shadow-lg);
  animation: fadeIn .15s ease;
}
.term-popup-hdr {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border-1);
}
.term-popup-hdr strong { color: var(--blue); font-size: 14px; font-weight: 700; }
.term-popup-close {
  color: var(--text-3); font-size: 18px; line-height: 1;
  padding: 0 2px; transition: var(--transition);
}
.term-popup-close:hover { color: var(--text-1); }
#termPopupDef { font-size: 13px; color: var(--text-2); line-height: 1.65; padding: 10px 14px; }
.term-popup-example {
  display: block; font-size: 12px; color: var(--orange);
  background: var(--bg-3);
  border-top: 1px solid var(--border-1);
  padding: 8px 14px;
  border-radius: 0 0 var(--r-md) var(--r-md);
}

/* Confirm Modal */
.confirm-modal { width: 400px; padding: 28px; }
.confirm-modal h3 { font-size: 17px; font-weight: 700; margin-bottom: 10px; display: flex; align-items: center; gap: 8px; }
.confirm-modal h3 i { color: var(--orange); }
.confirm-modal p { font-size: 14px; color: var(--text-2); margin-bottom: 20px; line-height: 1.6; }
.confirm-actions { display: flex; gap: 10px; justify-content: flex-end; }

/* =========================================================
   TOAST
   ========================================================= */
.toast {
  position: fixed; bottom: 24px; right: 24px; z-index: 999;
  display: flex; align-items: center; gap: 10px;
  background: var(--bg-3);
  border: 1px solid var(--border-2);
  border-radius: var(--r-md);
  padding: 12px 18px;
  font-size: 14px; font-weight: 500;
  box-shadow: var(--shadow-md);
  animation: toastIn .25s ease;
}
.toast i { color: var(--green); font-size: 16px; }
@keyframes toastIn {
  from { transform: translateX(80px); opacity: 0; }
  to   { transform: translateX(0); opacity: 1; }
}

/* =========================================================
   RESPONSIVE
   ========================================================= */
/* Narrow desktop / VS Code split-panel — sidebar narrows but stays visible */
@media (max-width: 900px) {
  :root { --sidebar-w: 188px; }
  .how-grid { grid-template-columns: 1fr 1fr; }
  .lesson-title { font-size: 20px; }
  .welcome-hero h1 { font-size: 28px; }
  .main-area { padding: 16px 16px 40px; }
  .lang-cards-row { gap: 12px; }
  .lang-card { padding: 18px 14px; }
  .lang-card h3 { font-size: 16px; }
  .lang-card p  { font-size: 13px; }
  .lc-icon { width: 42px; height: 42px; font-size: 20px; }
}
/* Stack editor / output panels at narrow widths */
@media (max-width: 700px) {
  .practice-layout, .challenge-workspace { grid-template-columns: 1fr; }
  .practice-left  { border-right: none; border-bottom: 1px solid var(--border-2); }
  .challenge-left { border-right: none; border-bottom: 1px solid var(--border-2); }
}
/* Mobile: collapse sidebar behind menu toggle */
@media (max-width: 620px) {
  .sidebar { display: none; }
  .sidebar.open { display: flex; position: fixed; top: var(--header-h); left: 0; bottom: 0; z-index: 150; }
}
@media (max-width: 600px) {
  .header-lang-nav span { display: none; }
  .lang-pill { padding: 7px 12px; }
  .progress-capsule { display: none; }
  .how-grid { grid-template-columns: 1fr; }
  .lang-cards-row { grid-template-columns: 1fr; }
}
/* Tablet portrait / large phone ────────────────────────── */
@media (max-width: 480px) {
  /* Header: let brand shrink, hide XP counter to save space */
  .header-brand { min-width: 0; }
  .xp-display   { display: none; }

  /* Tab bar: scroll horizontally so all 4 tabs stay reachable */
  .tab-bar {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  .tab-bar::-webkit-scrollbar { display: none; }
  .tab-btn { padding: 10px 14px; font-size: 13px; white-space: nowrap; }

  /* Welcome screen */
  .welcome-hero  { padding: 24px 0 20px; }
  .welcome-hero h1 { font-size: 22px; letter-spacing: -.5px; }
  .welcome-sub   { font-size: 15px; }
  .welcome-stat  { padding: 10px 16px; }
  .welcome-stat strong { font-size: 18px; }

  /* Lesson header: stack title + complete button vertically */
  .lesson-title { font-size: 17px; }
  .lesson-title-row { flex-direction: column; align-items: flex-start; gap: 10px; }

  /* Section cards: tighter padding */
  .section-card { padding: 16px 14px; }

  /* Modals: stretch to near full viewport width */
  .modal-box       { width: calc(100vw - 16px) !important; border-radius: var(--r-lg); }
  .confirm-modal   { width: calc(100vw - 16px); }
  .glossary-modal  { width: calc(100vw - 16px); }
}
/* Very small phones (360 px) ───────────────────────────── */
@media (max-width: 360px) {
  /* Hide brand label, keep the icon — saves ~110px in header */
  .brand-logo span { display: none; }
  .main-area       { padding: 12px 10px 40px; }
  .welcome-stat-row { gap: 8px; }
  .welcome-stat    { padding: 8px 12px; }
}