/* ═══════════════════════════════════════════════════════
   AI FUNDAMENTALS – Professional Educational Stylesheet
   Colors: Light Blue, Green, Saffron, Red, Violet + accents
   ═══════════════════════════════════════════════════════ */

/* ── CSS VARIABLES ── */
:root {
  --blue:    rgb(30, 100, 200);
  --blue-lt: rgb(220, 235, 255);
  --green:   rgb(20, 140, 80);
  --green-lt:rgb(210, 245, 225);
  --saffron: rgb(220, 110, 20);
  --saff-lt: rgb(255, 238, 210);
  --red:     rgb(190, 30, 50);
  --red-lt:  rgb(255, 220, 225);
  --violet:  rgb(110, 30, 180);
  --viol-lt: rgb(235, 220, 255);
  --white:   #ffffff;
  --dark:    rgb(20, 20, 40);
  --text:    rgb(15, 15, 35);
  --border-r:rgb(30, 100, 200);
  --shadow:  rgba(30, 60, 120, 0.18);
  --header-bg: linear-gradient(135deg, rgb(10,30,80) 0%, rgb(20,80,160) 50%, rgb(10,50,120) 100%);
  --nav-bg:    rgb(15, 40, 90);
  --page-bg:   linear-gradient(160deg, rgb(235,245,255) 0%, rgb(240,255,245) 50%, rgb(255,248,235) 100%);
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Source Sans 3', sans-serif;
  font-weight: 700;
  background: var(--page-bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.7;
}

/* ── HEADER ── */
.site-header {
  background: var(--header-bg);
  color: var(--white);
  padding: 40px 24px 32px;
  text-align: center;
  border-bottom: 5px solid rgb(100, 180, 255);
  position: relative;
  overflow: hidden;
}
.site-header::before {
  content: '';
  position: absolute; inset: 0;
  background: repeating-linear-gradient(
    45deg,
    transparent, transparent 60px,
    rgba(255,255,255,0.03) 60px, rgba(255,255,255,0.03) 61px
  );
}
.header-inner { position: relative; z-index: 1; max-width: 960px; margin: 0 auto; }
.header-badge { font-size: 56px; margin-bottom: 8px; }
.site-title {
  font-family: 'Playfair Display', serif;
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 900;
  letter-spacing: 1px;
  text-shadow: 0 2px 12px rgba(0,0,0,0.5);
  line-height: 1.2;
  margin-bottom: 10px;
}
.site-subtitle {
  font-size: 1.15rem;
  font-weight: 700;
  color: rgb(180, 220, 255);
  letter-spacing: 2px;
  margin-bottom: 24px;
}

/* ── PRINT BUTTON ── */
.print-btn {
  background: rgb(255, 165, 30);
  color: rgb(20, 20, 40);
  border: none;
  padding: 10px 28px;
  font-size: 1rem;
  font-weight: 800;
  border-radius: 30px;
  cursor: pointer;
  letter-spacing: 1px;
  box-shadow: 0 4px 15px rgba(255,165,30,0.4);
  transition: transform 0.2s, box-shadow 0.2s;
}
.print-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(255,165,30,0.55);
}

/* ── STICKY NAV ── */
.sticky-nav {
  position: sticky; top: 0; z-index: 999;
  background: var(--nav-bg);
  border-bottom: 3px solid rgb(100, 180, 255);
  box-shadow: 0 3px 16px rgba(0,0,0,0.25);
}
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  padding: 10px 16px;
  display: flex; flex-wrap: wrap;
  align-items: center; gap: 8px;
}
.nav-label {
  color: rgb(180, 220, 255);
  font-weight: 800; font-size: 0.9rem;
  letter-spacing: 1px; margin-right: 4px;
}
.nav-btn {
  background: rgb(255, 255, 255, 0.10);
  color: rgb(255, 255, 255);
  border: 2px solid rgb(100, 180, 255);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 800;
  cursor: pointer;
  letter-spacing: 0.5px;
  transition: all 0.2s;
  font-family: 'Source Sans 3', sans-serif;
}
.nav-btn:hover {
  background: rgb(100, 180, 255);
  color: rgb(10, 30, 80);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(100,180,255,0.35);
}

/* ── DISCLAIMER ── */
.disclaimer {
  background: rgb(255, 245, 210);
  border-left: 6px solid rgb(220, 110, 20);
  border-bottom: 2px solid rgb(220, 110, 20);
  padding: 12px 24px;
  font-size: 0.95rem;
  font-weight: 800;
  color: rgb(100, 50, 10);
  text-align: center;
}

/* ── MAIN CONTENT ── */
.main-content {
  max-width: 1100px; margin: 0 auto;
  padding: 32px 20px 60px;
  display: flex; flex-direction: column; gap: 40px;
}

/* ── CONTENT SECTION ── */
.content-section {
  background: var(--white);
  border-radius: 16px;
  box-shadow: 0 4px 30px var(--shadow);
  overflow: hidden;
  border: 3px solid var(--border-r);
}

.section-header {
  display: flex; align-items: center; gap: 14px;
  padding: 18px 28px;
  border-bottom: 3px solid rgba(0,0,0,0.1);
}
.section-header h2 {
  font-family: 'Playfair Display', serif;
  font-size: clamp(1.2rem, 2.5vw, 1.7rem);
  font-weight: 900;
  color: var(--white);
  letter-spacing: 0.5px;
}
.section-icon { font-size: 1.8rem; }

.s1 { background: linear-gradient(135deg, rgb(20,80,180), rgb(50,130,230)); }
.s2 { background: linear-gradient(135deg, rgb(15,110,60), rgb(30,170,100)); }
.s3 { background: linear-gradient(135deg, rgb(80,20,150), rgb(140,60,220)); }
.s4 { background: linear-gradient(135deg, rgb(180,30,50), rgb(220,80,80)); }

.section-body {
  padding: 24px 28px;
  display: flex; flex-direction: column; gap: 20px;
}

/* ── CARDS ── */
.card {
  border-radius: 12px;
  padding: 20px 24px;
  border-left: 6px solid;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}
.card h3 {
  font-family: 'Playfair Display', serif;
  font-size: 1.2rem; font-weight: 900;
  margin-bottom: 10px;
}
.card h4 {
  font-size: 1.05rem; font-weight: 800;
  margin-bottom: 10px;
}
.card p { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }

.blue-card   { background: var(--blue-lt);  border-color: var(--blue);    color: rgb(10,30,90); }
.green-card  { background: var(--green-lt); border-color: var(--green);   color: rgb(5,50,25); }
.saffron-card{ background: var(--saff-lt);  border-color: var(--saffron); color: rgb(80,40,5); }
.red-card    { background: var(--red-lt);   border-color: var(--red);     color: rgb(80,10,20); }
.violet-card { background: var(--viol-lt);  border-color: var(--violet);  color: rgb(50,10,80); }

/* ── BULLET LIST ── */
.bullet-list {
  list-style: none; padding: 0; margin: 0;
  display: flex; flex-direction: column; gap: 8px;
}
.bullet-list li {
  padding-left: 22px; position: relative;
  font-size: 1rem; font-weight: 700; line-height: 1.6;
}
.bullet-list li::before {
  content: '▶';
  position: absolute; left: 0; top: 2px;
  font-size: 0.7rem; color: inherit;
}

/* ── TAG ROW ── */
.tag-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }
.tag {
  background: rgb(30, 100, 200);
  color: #fff; padding: 4px 14px;
  border-radius: 20px; font-size: 0.82rem;
  font-weight: 800; letter-spacing: 0.5px;
}

/* ── TOOLS LINE ── */
.tools-line {
  margin-top: 10px !important;
  font-size: 0.92rem !important;
  background: rgba(0,0,0,0.07);
  padding: 8px 12px; border-radius: 8px;
}

/* ── SUB HEADING ── */
.sub-heading {
  font-family: 'Playfair Display', serif;
  font-size: 1.35rem; font-weight: 900;
  color: rgb(20, 80, 180);
  border-bottom: 3px solid rgb(20, 80, 180);
  padding-bottom: 8px; margin-top: 8px;
}

/* ── TABLE ── */
.table-wrapper { overflow-x: auto; border-radius: 10px; border: 2px solid var(--border-r); }
.data-table {
  width: 100%; border-collapse: collapse;
  font-size: 0.9rem; font-weight: 700;
}
.data-table thead {
  background: linear-gradient(90deg, rgb(20,80,180), rgb(50,140,100));
  color: #fff;
}
.data-table th {
  padding: 14px 12px; text-align: left;
  font-size: 0.92rem; font-weight: 800;
  border-right: 1px solid rgba(255,255,255,0.2);
}
.data-table td {
  padding: 12px 12px;
  border-bottom: 1px solid rgb(200, 220, 240);
  border-right: 1px solid rgb(200, 220, 240);
  vertical-align: top; line-height: 1.5;
}
.data-table tbody tr:nth-child(odd)  { background: rgb(235,245,255); }
.data-table tbody tr:nth-child(even) { background: rgb(240,255,245); }
.data-table tbody tr:hover { background: rgb(255, 248, 220); transition: background 0.2s; }

/* ── CANVAS WRAPPER ── */
.canvas-wrapper {
  overflow-x: auto;
  border-radius: 10px;
  background: rgb(248, 252, 255);
  border: 2px solid var(--border-r);
  padding: 10px;
  min-height: 200px;
  display: flex; justify-content: center; align-items: flex-start;
}
canvas { display: block; }

/* ── FOOTER ── */
.site-footer {
  background: rgb(10, 30, 70);
  color: rgb(200, 220, 255);
  text-align: center; padding: 28px 20px;
  border-top: 4px solid rgb(100, 180, 255);
  font-weight: 700; font-size: 0.95rem;
  display: flex; flex-direction: column; gap: 10px; align-items: center;
}

/* ── PRINT STYLES ── */
@media print {
  .sticky-nav, .print-btn { display: none !important; }
  body { background: #fff; }
  .content-section { box-shadow: none; border: 2px solid #333; page-break-inside: avoid; }
  .site-header { print-color-adjust: exact; -webkit-print-color-adjust: exact; }
  .section-header { print-color-adjust: exact; -webkit-print-color-adjust: exact; }
  canvas { max-width: 100%; }
}

/* ── RESPONSIVE ── */
@media (max-width: 700px) {
  .section-body { padding: 16px; }
  .card { padding: 14px 16px; }
  .nav-inner { gap: 6px; }
  .nav-btn { font-size: 0.78rem; padding: 5px 10px; }
  .data-table th, .data-table td { font-size: 0.8rem; padding: 8px; }
}