/* =========================================================================
   FINESE SCHOOL — design system
   Themed to match the FINESE DATA brand: orange gradient accents, deep
   navy surfaces (header / hero / footer), and a clean white reading body.
   Still no external font/icon CDNs on purpose — the app must work with
   zero network connection once a page has loaded. The display font names
   "Plus Jakarta Sans" (FINESE DATA's typeface) first and gracefully falls
   back to the system sans when offline, so nothing here blocks on a CDN.
   ========================================================================= */

:root {
  /* ---- FINESE DATA brand ---- */
  --brand-orange: #f97316;          /* primary brand orange */
  --brand-orange-light: #fba918;    /* top of the logo gradient */
  --brand-orange-deep: #ea580c;     /* bottom of the logo gradient */
  --brand-gradient: linear-gradient(135deg, #fba918 0%, #f97316 55%, #ea580c 100%);
  --brand-dark: #050b18;            /* deep navy used on header/hero/footer */
  --brand-dark-2: #0b1626;
  --brand-hero: radial-gradient(circle at 78% 25%, rgba(249, 115, 22, 0.20) 0%, rgba(5, 11, 24, 0) 55%), #050b18;

  --bg: #ffffff;
  --surface: #ffffff;
  --surface-2: #f8fafc;
  --ink: #0f172a;
  --muted: #64748b;
  --border: #e6e8ec;
  --border-strong: #cbd2dc;
  --accent: #f97316;           /* brand orange default; overridden per-topic via inline style */
  --accent-ink: #ffffff;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.05), 0 10px 28px -14px rgba(15, 23, 42, 0.18);

  --font-body: "Plus Jakarta Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-display: "Plus Jakarta Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", "Cascadia Code", Menlo, Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }
button { font-family: inherit; }

img, svg { max-width: 100%; display: block; }

::selection { background: color-mix(in srgb, var(--accent) 30%, transparent); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ---------- header ---------- */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 28px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  background: var(--brand-hero);
  position: sticky;
  top: 0;
  z-index: 40;
}
.brand { display: flex; align-items: center; gap: 12px; text-decoration: none; }
.brand-logo { height: 40px; width: auto; display: block; }
.brand-mark { font-size: 22px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.12; }
.brand-name {
  font-family: var(--font-display); font-weight: 800; font-size: 17px;
  letter-spacing: 0.02em; color: #ffffff;
}
.brand-name b { color: var(--brand-orange); font-weight: 800; }
.brand-tag { font-size: 11px; color: #94a3b8; letter-spacing: .02em; }

.net-badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 11.5px; font-weight: 600;
  padding: 5px 10px 5px 8px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: rgba(255, 255, 255, 0.06);
  color: #cbd5e1;
}
.net-dot { width: 7px; height: 7px; border-radius: 50%; background: #cbd5e1; }
.net-badge.is-online .net-dot { background: #34d399; }
.net-badge.is-online { color: #6ee7b7; border-color: rgba(52, 211, 153, 0.35); background: rgba(52, 211, 153, 0.10); }
.net-badge.is-offline .net-dot { background: #f87171; }
.net-badge.is-offline { color: #fca5a5; border-color: rgba(248, 113, 113, 0.35); background: rgba(248, 113, 113, 0.10); }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  font-size: 13.5px; font-weight: 600;
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface);
  cursor: pointer;
  text-decoration: none;
  color: var(--ink);
  transition: transform .08s ease, filter .15s ease;
}
.btn:hover { filter: brightness(0.98); }
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: var(--brand-gradient);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 8px 18px -8px rgba(249, 115, 22, 0.6);
}
.btn-primary:hover { filter: brightness(1.05); }
.btn:disabled { opacity: .5; cursor: not-allowed; }

/* =========================================================================
   HOME PAGE
   ========================================================================= */

.hero {
  position: relative;
  overflow: hidden;
  background: var(--brand-hero);
  color: #ffffff;
  padding: 72px 24px 64px;
  text-align: center;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}
/* faint brand mark watermark on the right */
.hero::after {
  content: "";
  position: absolute;
  right: -60px; top: 50%; transform: translateY(-50%);
  width: 420px; height: 420px;
  background: url("../img/finese-mark.png") no-repeat center / contain;
  opacity: 0.06;
  pointer-events: none;
}
.hero-eyebrow {
  display: inline-block;
  font-size: 12px; font-weight: 700; letter-spacing: .18em;
  text-transform: uppercase; color: var(--brand-orange);
  margin-bottom: 16px;
}
.hero > * { position: relative; z-index: 1; }
.hero h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 4.4vw, 48px);
  line-height: 1.12;
  letter-spacing: -0.01em;
  margin: 0 auto 18px;
  max-width: 820px;
}
.hero-highlight {
  background: var(--brand-gradient);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: var(--brand-orange);
}
.hero-sub {
  color: #94a3b8;
  font-size: 16px;
  max-width: 680px;
  margin: 0 auto;
}
.hero-stats {
  display: flex; justify-content: center; gap: 44px;
  margin-top: 40px; flex-wrap: wrap;
}
.hero-stat {
  display: flex; flex-direction: column; align-items: center;
  padding-left: 22px; border-left: 2px solid rgba(249, 115, 22, 0.35);
}
.hero-stat strong { font-family: var(--font-display); font-weight: 800; font-size: 30px; color: #ffffff; }
.hero-stat span { font-size: 11.5px; color: #94a3b8; text-transform: uppercase; letter-spacing: .06em; margin-top: 2px; }

.topic-grid {
  max-width: 1180px;
  margin: 24px auto 60px;
  padding: 0 24px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 18px;
}
.topic-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-decoration: none;
  color: var(--ink);
  box-shadow: var(--shadow);
  transition: transform .15s ease, border-color .15s ease;
  border-top: 3px solid var(--accent);
  display: flex; flex-direction: column;
}
.topic-card:hover { transform: translateY(-3px); border-color: var(--border-strong); }
.topic-card-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 10px; }
.topic-card-icon {
  font-size: 26px;
  width: 46px; height: 46px;
  display: grid; place-items: center;
  background: color-mix(in srgb, var(--accent) 14%, white);
  border-radius: 12px;
}
.topic-card-progress-ring {
  font-size: 11px; font-weight: 700;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, white);
  border-radius: 999px;
  padding: 4px 9px;
}
.topic-card h2 { font-family: var(--font-display); font-size: 19px; margin: 4px 0 2px; }
.topic-card-tagline { font-size: 12.5px; color: var(--accent); font-weight: 600; margin: 0 0 8px; }
.topic-card-desc { font-size: 13px; color: var(--muted); flex: 1; margin: 0 0 14px; line-height: 1.5; }
.topic-card-footer {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 12px; color: var(--muted);
  padding-top: 12px; border-top: 1px dashed var(--border);
}
.topic-card-arrow { color: var(--accent); font-weight: 600; }

.how-it-works { max-width: 1180px; margin: 0 auto 70px; padding: 0 24px; }
.how-it-works h2 { text-align: center; font-family: var(--font-display); font-size: 24px; margin-bottom: 28px; }
.how-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; }
.how-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; }
.how-icon { font-size: 24px; margin-bottom: 10px; }
.how-card h3 { font-size: 15px; margin: 0 0 8px; }
.how-card p { font-size: 13px; color: var(--muted); margin: 0; line-height: 1.55; }

/* =========================================================================
   TOPIC PAGE
   ========================================================================= */

.topic-shell { display: flex; flex-direction: column; min-height: calc(100vh - 130px); }

.topic-hero {
  display: flex; align-items: center; gap: 20px;
  padding: 26px 28px;
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 10%, white), var(--bg) 70%);
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.topic-hero-icon {
  font-size: 34px;
  width: 62px; height: 62px;
  display: grid; place-items: center;
  background: var(--surface);
  border-radius: 16px;
  box-shadow: var(--shadow);
  flex-shrink: 0;
}
.topic-hero-text { flex: 1; min-width: 240px; }
.topic-hero-eyebrow { font-size: 11.5px; text-transform: uppercase; letter-spacing: .1em; color: var(--accent); font-weight: 700; }
.topic-hero-text h1 { font-family: var(--font-display); font-size: 26px; margin: 3px 0 4px; }
.topic-hero-text p { margin: 0; color: var(--muted); font-size: 13.5px; max-width: 560px; }
.topic-hero-meta { display: flex; flex-direction: column; gap: 6px; min-width: 160px; }
.topic-progress-bar { width: 160px; height: 6px; background: var(--border); border-radius: 999px; overflow: hidden; }
.topic-progress-fill { height: 100%; width: 0%; background: var(--accent); transition: width .3s ease; }
#topic-progress-label { font-size: 11.5px; color: var(--muted); }

.topic-body {
  flex: 1;
  display: grid;
  grid-template-columns: 240px 1fr 300px;
  gap: 0;
  align-items: start;
}

/* ---------- lesson nav (left) ---------- */
.lesson-nav {
  position: sticky; top: 64px;
  align-self: start;
  max-height: calc(100vh - 64px);
  overflow-y: auto;
  padding: 20px 14px;
  border-right: 1px solid var(--border);
}
.lesson-nav-label {
  font-size: 10.5px; text-transform: uppercase; letter-spacing: .1em;
  color: var(--muted); padding: 0 10px; margin-bottom: 6px;
}
.lesson-nav-label-secondary { margin-top: 22px; }
.lesson-nav-item {
  display: flex; align-items: center; gap: 9px;
  width: 100%; text-align: left;
  background: none; border: none;
  padding: 8px 10px; border-radius: 8px;
  font-size: 12.8px; color: var(--ink);
  cursor: pointer;
}
.lesson-nav-item:hover { background: var(--surface-2); }
.lesson-nav-item.is-active { background: color-mix(in srgb, var(--accent) 12%, white); color: var(--accent); font-weight: 600; }
.lesson-check {
  width: 15px; height: 15px; border-radius: 50%;
  border: 1.5px solid var(--border-strong);
  flex-shrink: 0;
  display: inline-block;
}
.lesson-check.is-done { background: var(--accent); border-color: var(--accent); position: relative; }
.lesson-check.is-done::after {
  content: '✓'; position: absolute; inset: 0;
  display: grid; place-items: center;
  color: #fff; font-size: 10px; font-weight: 700;
}

.other-topics-list { display: flex; flex-direction: column; gap: 2px; }
.other-topic-link {
  display: flex; align-items: center; gap: 8px;
  padding: 7px 10px; border-radius: 8px;
  font-size: 12.5px; text-decoration: none; color: var(--muted);
}
.other-topic-link:hover { background: var(--surface-2); color: var(--t-accent); }
.other-topic-icon { font-size: 14px; }

/* ---------- lesson content (center) ---------- */
.lesson-content { padding: 28px 34px; max-width: 760px; }
.lesson-loading { color: var(--muted); font-style: italic; padding: 40px 0; }

.lesson h2 { font-family: var(--font-display); font-size: 25px; margin: 0 0 6px; }
.lesson-hook {
  font-size: 14.5px; color: var(--accent);
  font-weight: 600; margin: 0 0 20px;
  padding-left: 12px; border-left: 3px solid var(--accent);
}
.lesson p.body-p { font-size: 14.5px; color: #2b2c2e; margin: 0 0 14px; line-height: 1.7; }
.lesson p.body-p code, .lesson .example-box code { font-family: var(--font-mono); font-size: 12.8px; background: var(--surface-2); border: 1px solid var(--border); padding: 1px 5px; border-radius: 5px; }

.code-block { margin: 20px 0; border-radius: var(--radius-sm); overflow: hidden; border: 1px solid #2a2d33; }
.code-head {
  display: flex; align-items: center; gap: 8px;
  background: #23262c; color: #b7bcc4;
  font-size: 11px; text-transform: uppercase; letter-spacing: .07em;
  padding: 8px 12px;
}
.code-head span:first-child { flex: 1; }
.copy-btn {
  background: none; border: 1px solid #454952; color: #d5d8dd;
  font-size: 10.5px; padding: 3px 9px; border-radius: 6px; cursor: pointer;
}
.copy-btn:hover { border-color: #6b7280; }
.copy-btn.is-copied { border-color: var(--accent); color: var(--accent); }
.code-block pre {
  margin: 0; padding: 14px 16px;
  background: #1b1d21; color: #e7e9ec;
  font-family: var(--font-mono); font-size: 12.6px; line-height: 1.6;
  overflow-x: auto; white-space: pre;
}

.example-box {
  background: color-mix(in srgb, var(--accent) 7%, white);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 14px 16px; margin: 20px 0;
}
.example-box strong { font-size: 11.5px; text-transform: uppercase; letter-spacing: .06em; color: var(--accent); display: block; margin-bottom: 6px; }
.example-box p { margin: 0; font-size: 13.8px; line-height: 1.6; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 22px 0; }
@media (max-width: 900px) { .two-col { grid-template-columns: 1fr; } }
.best-practices, .pitfalls { background: var(--surface-2); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 14px 16px; }
.best-practices h3, .pitfalls h3 { font-size: 12.5px; margin: 0 0 9px; }
.best-practices ul, .pitfalls ul { margin: 0; padding-left: 18px; font-size: 12.6px; line-height: 1.55; color: #34363a; }
.best-practices li, .pitfalls li { margin-bottom: 7px; }

.prompts-box { margin-top: 22px; }
.prompts-box h3 { font-size: 12.5px; margin: 0 0 10px; color: var(--muted); }
.prompt-chips { display: flex; flex-wrap: wrap; gap: 8px; }
.prompt-chip {
  background: var(--surface); border: 1px solid var(--border-strong);
  border-radius: 999px; padding: 8px 14px;
  font-size: 12.2px; cursor: pointer; text-align: left;
  color: var(--ink);
}
.prompt-chip:hover { border-color: var(--accent); color: var(--accent); }

.lesson-nav-footer { display: flex; justify-content: space-between; margin-top: 30px; padding-top: 18px; border-top: 1px solid var(--border); }

/* ---------- AI panel (right) ---------- */
.ai-panel {
  position: sticky; top: 64px;
  align-self: start;
  max-height: calc(100vh - 64px);
  overflow-y: auto;
  padding: 20px 18px;
  border-left: 1px solid var(--border);
  background: var(--surface-2);
  display: flex; flex-direction: column; gap: 10px;
}
.ai-panel-header { display: flex; align-items: center; justify-content: space-between; font-size: 13.5px; font-weight: 700; }
.ai-panel-sub { font-size: 11.5px; color: var(--muted); line-height: 1.5; margin: 0 0 4px; }
.ai-field { display: flex; flex-direction: column; gap: 4px; }
.ai-field label { font-size: 10.5px; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); }
.ai-field select, .ai-field input {
  padding: 8px 9px; border-radius: 8px; border: 1px solid var(--border-strong);
  font-size: 12.6px; background: var(--surface); color: var(--ink);
}
.socratic-row { display: flex; align-items: center; gap: 7px; font-size: 12px; color: var(--muted); margin: 2px 0; }
.socratic-row input { accent-color: var(--accent); }

.ai-chat { display: flex; flex-direction: column; gap: 8px; min-height: 20px; }
.ai-msg { font-size: 12.6px; padding: 9px 11px; border-radius: 10px; line-height: 1.5; }
.ai-msg-user { background: color-mix(in srgb, var(--accent) 14%, white); align-self: flex-end; max-width: 92%; }
.ai-msg-assistant { background: var(--surface); border: 1px solid var(--border); max-width: 96%; white-space: pre-wrap; }
.ai-msg-error { background: #fdf1f1; border: 1px solid #f0d2ce; color: #b23a31; }
.ai-msg-pending { color: var(--muted); font-style: italic; }

.ai-composer { display: flex; flex-direction: column; gap: 8px; margin-top: auto; padding-top: 8px; }
.ai-composer textarea {
  width: 100%; resize: vertical;
  border: 1px solid var(--border-strong); border-radius: 9px;
  padding: 9px 10px; font-family: inherit; font-size: 12.8px;
}

/* =========================================================================
   404 page
   ========================================================================= */
.not-found { max-width: 640px; margin: 70px auto; text-align: center; padding: 0 24px; }
.not-found-icon { font-size: 42px; margin-bottom: 12px; }
.not-found h1 { font-family: var(--font-display); font-size: 24px; }
.not-found p { color: var(--muted); margin-bottom: 24px; }
.not-found-grid { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-top: 30px; }
.not-found-chip {
  border: 1px solid var(--border-strong); border-radius: 999px;
  padding: 7px 13px; font-size: 12.5px; text-decoration: none; color: var(--ink);
}
.not-found-chip:hover { border-color: var(--accent); color: var(--accent); }

/* =========================================================================
   Footer
   ========================================================================= */
.site-footer {
  background: var(--brand-dark);
  color: #94a3b8;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding: 44px 24px 40px;
  margin-top: 60px;
}
.footer-inner {
  max-width: 1180px; margin: 0 auto;
  display: flex; align-items: center; gap: 22px; flex-wrap: wrap;
  justify-content: space-between;
}
.footer-brand { display: flex; align-items: center; gap: 14px; }
.footer-logo { height: 54px; width: auto; }
.footer-brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.footer-brand-name { color: #fff; font-family: var(--font-display); font-weight: 800; font-size: 15px; letter-spacing: .02em; }
.footer-brand-name b { color: var(--brand-orange); }
.footer-brand-tag { font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--brand-orange); margin-top: 2px; }
.site-footer p { font-size: 11.5px; color: #64748b; max-width: 520px; margin: 0; line-height: 1.6; }
.footer-copy { color: #475569; font-size: 11px; }

/* =========================================================================
   Responsive
   ========================================================================= */
@media (max-width: 1080px) {
  .topic-body { grid-template-columns: 210px 1fr; }
  .ai-panel { grid-column: 1 / -1; position: static; max-height: none; border-left: none; border-top: 1px solid var(--border); }
}
@media (max-width: 720px) {
  .topic-body { grid-template-columns: 1fr; }
  .lesson-nav { position: static; max-height: none; border-right: none; border-bottom: 1px solid var(--border); }
  .lesson-content { padding: 22px 18px; }
  .site-header { padding: 12px 16px; }
  .brand-logo { height: 34px; }
  .hero { padding: 48px 20px 44px; }
  .hero-stats { gap: 24px; }
  .footer-inner { flex-direction: column; align-items: flex-start; gap: 16px; }
}

/* =========================================================================
   Print — used by the browser's native "Save as PDF"
   ========================================================================= */
@media print {
  .site-header, .lesson-nav, .ai-panel, .site-footer, .topic-progress-bar { display: none !important; }
  .topic-body { display: block; }
  .lesson-content { max-width: 100%; padding: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; animation: none !important; }
}