/* ============================================================
   TELNOVAT — Telecom Innovation
   Global Stylesheet
   ============================================================ */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

/* ---------- CSS Variables ---------- */
:root {
  --bg-primary:    #0b1e30;
  --bg-secondary:  #102840;
  --bg-card:       #102840;
  --bg-card-hover: #163350;
  --border:        rgba(6, 182, 212, 0.25);
  --border-hover:  rgba(6, 182, 212, 0.50);

  --accent:        #06b6d4;   /* cyan */
  --accent-bright: #22d3ee;
  --accent-dim:    rgba(6, 182, 212, 0.12);
  --blue:          #3b82f6;
  --blue-dim:      rgba(59, 130, 246, 0.12);
  --purple:        #8b5cf6;

  --text-primary:  #f0f9ff;
  --text-secondary:#94a3b8;
  --text-muted:    #64748b;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;

  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 40px rgba(6, 182, 212, 0.08);

  --transition: 0.22s ease;
  --font-body: 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-bright); }
ul { list-style: none; }

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
}
h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.4rem); }
h3 { font-size: clamp(1.15rem, 2vw, 1.5rem); }
h4 { font-size: 1.1rem; }

p { color: var(--text-secondary); margin-bottom: 1em; }
p:last-child { margin-bottom: 0; }

.lead { font-size: 1.15rem; color: var(--text-secondary); line-height: 1.8; }

code, .mono {
  font-family: var(--font-mono);
  background: var(--accent-dim);
  color: var(--accent-bright);
  padding: 2px 7px;
  border-radius: 4px;
  font-size: 0.88em;
}

pre {
  background: rgba(0,0,0,0.4);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--accent-bright);
  margin: 1.5rem 0;
}

/* ---------- Layout ---------- */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.container--narrow { max-width: 820px; }
.container--wide   { max-width: 1440px; }

section { padding: 5rem 0; }

.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 2rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.75rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; }

/* ---------- Header / Navigation ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 999;
  background: rgba(5, 13, 26, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent), var(--blue));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 0.85rem;
  color: #fff;
  flex-shrink: 0;
}

.logo-text { display: flex; flex-direction: column; line-height: 1.1; }
.logo-name { font-weight: 700; font-size: 1.05rem; color: var(--text-primary); }
.logo-tagline { font-size: 0.65rem; color: var(--text-muted); letter-spacing: 0.08em; text-transform: uppercase; }

.site-nav { display: flex; align-items: center; gap: 2rem; }

.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition);
  position: relative;
  padding-bottom: 2px;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px; left: 0;
  width: 0; height: 2px;
  background: var(--accent);
  transition: width var(--transition);
  border-radius: 2px;
}
.nav-link:hover, .nav-link.active { color: var(--text-primary); }
.nav-link:hover::after, .nav-link.active::after { width: 100%; }

.nav-cta {
  background: linear-gradient(135deg, var(--accent), var(--blue));
  color: #fff !important;
  padding: 0.5rem 1.25rem;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.875rem;
  transition: opacity var(--transition), transform var(--transition);
}
.nav-cta::after { display: none; }
.nav-cta:hover { opacity: 0.9; transform: translateY(-1px); color: #fff; }

/* Mobile menu toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.menu-toggle span {
  width: 24px; height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

/* ---------- Footer ---------- */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 4rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-brand p { font-size: 0.9rem; margin-top: 0.75rem; max-width: 280px; }

.footer-col h4 {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 1rem;
}
.footer-col ul { display: flex; flex-direction: column; gap: 0.6rem; }
.footer-col a { font-size: 0.9rem; color: var(--text-secondary); }
.footer-col a:hover { color: var(--accent); }

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-bottom p { font-size: 0.825rem; color: var(--text-muted); margin: 0; }

.social-links { display: flex; gap: 0.75rem; }
.social-link {
  width: 36px; height: 36px;
  border-radius: 50%;
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-secondary);
  font-size: 0.8rem;
  transition: all var(--transition);
}
.social-link:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-dim);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--blue));
  color: #fff;
}
.btn-primary:hover { opacity: 0.9; transform: translateY(-2px); color: #fff; box-shadow: 0 8px 24px rgba(6,182,212,0.3); }

.btn-outline {
  background: transparent;
  border: 1px solid var(--border-hover);
  color: var(--text-primary);
}
.btn-outline:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-dim); }

.btn-sm { padding: 0.5rem 1.25rem; font-size: 0.825rem; }
.btn-lg { padding: 1rem 2.25rem; font-size: 1rem; }

/* ---------- Cards ---------- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  transition: all var(--transition);
  box-shadow: var(--shadow-card);
}
.card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.card-img {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: 1.25rem;
}

.card-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius: 50px;
  margin-bottom: 0.75rem;
}
.tag-cyan  { background: var(--accent-dim);  color: var(--accent); }
.tag-blue  { background: var(--blue-dim);    color: var(--blue); }
.tag-purple{ background: rgba(139,92,246,.12); color: var(--purple); }

.card-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 1rem;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: 7rem 0 6rem;
  text-align: center;
}

.hero::before {
  content: '';
  position: absolute;
  top: -120px; left: 50%;
  transform: translateX(-50%);
  width: 900px; height: 600px;
  background: radial-gradient(ellipse, rgba(6,182,212,0.12) 0%, transparent 65%);
  pointer-events: none;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-dim);
  border: 1px solid var(--border-hover);
  padding: 0.35rem 1rem;
  border-radius: 50px;
  margin-bottom: 1.5rem;
}

.hero h1 { margin-bottom: 1.25rem; }
.hero h1 em { font-style: normal; color: var(--accent); }

.hero-desc {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 620px;
  margin: 0 auto 2.5rem;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 3rem;
  margin-top: 4rem;
  flex-wrap: wrap;
}

.stat-item { text-align: center; }
.stat-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
}
.stat-label {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 0.3rem;
}

/* ---------- Section Headers ---------- */
.section-header { text-align: center; margin-bottom: 3.5rem; }
.section-eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.75rem;
}
.section-header p { max-width: 560px; margin: 0.75rem auto 0; }

/* ---------- Feature / Topic Grid ---------- */
.feature-card {
  padding: 1.75rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}
.feature-card:hover { border-color: var(--border-hover); background: var(--bg-card-hover); }

.feature-icon {
  width: 48px; height: 48px;
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 1rem;
  background: var(--accent-dim);
}

/* ---------- Course Card ---------- */
.course-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
}
.course-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
  box-shadow: 0 16px 40px rgba(0,0,0,0.5), var(--shadow-glow);
}
.course-card-header {
  padding: 2rem 1.75rem 1.5rem;
  background: linear-gradient(135deg, rgba(6,182,212,0.1), rgba(59,130,246,0.08));
  border-bottom: 1px solid var(--border);
}
.course-card-body { padding: 1.75rem; flex: 1; display: flex; flex-direction: column; }
.course-card-footer {
  padding: 1.25rem 1.75rem;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.rating {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: #fbbf24;
}

.course-stats {
  display: flex;
  gap: 1rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}
.course-stat {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ---------- Blog Card ---------- */
.blog-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
}
.blog-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-card), var(--shadow-glow);
}
.blog-card-body { padding: 1.5rem; flex: 1; display: flex; flex-direction: column; }
.blog-card h3 { margin-bottom: 0.6rem; font-size: 1.1rem; }
.blog-card h3 a { color: var(--text-primary); }
.blog-card h3 a:hover { color: var(--accent); }

/* ---------- Article / Blog Post ---------- */
.article-header {
  padding: 5rem 0 3rem;
  text-align: center;
}
.article-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 1.25rem;
  flex-wrap: wrap;
}
.article-meta .dot { opacity: 0.4; }

.article-body {
  max-width: 780px;
  margin: 0 auto;
  padding: 0 1.5rem 5rem;
}
.article-body h2 { margin: 2.25rem 0 1rem; }
.article-body h3 { margin: 1.75rem 0 0.75rem; color: var(--accent-bright); }
.article-body p  { margin-bottom: 1.25rem; }
.article-body ul, .article-body ol { padding-left: 1.5rem; margin-bottom: 1.25rem; }
.article-body li { color: var(--text-secondary); margin-bottom: 0.5rem; list-style: disc; }
.article-body blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.75rem 1.25rem;
  background: var(--accent-dim);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
}
.article-body blockquote p { color: var(--text-primary); margin: 0; }

.formula-box {
  background: rgba(0,0,0,0.4);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  font-family: var(--font-mono);
  color: var(--accent-bright);
  font-size: 0.95rem;
  overflow-x: auto;
}

.info-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9rem;
}
.info-table th, .info-table td {
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  text-align: left;
}
.info-table th {
  background: var(--accent-dim);
  color: var(--accent);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}
.info-table td { color: var(--text-secondary); }
.info-table tr:nth-child(even) td { background: rgba(255,255,255,0.02); }

/* ---------- Coupon Box ---------- */
.coupon-box {
  background: linear-gradient(135deg, rgba(6,182,212,0.1), rgba(59,130,246,0.08));
  border: 1px solid var(--border-hover);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  margin: 2rem 0;
  text-align: center;
}
.coupon-code {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.12em;
  background: var(--accent-dim);
  border: 1px dashed var(--border-hover);
  display: inline-block;
  padding: 0.5rem 1.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
  margin: 0.75rem 0;
}
.coupon-code:hover { background: var(--accent); color: #fff; }

/* ---------- Curriculum Accordion ---------- */
.curriculum-section {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-bottom: 0.5rem;
  overflow: hidden;
}
.curriculum-section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  background: var(--bg-card);
  cursor: pointer;
  transition: background var(--transition);
}
.curriculum-section-header:hover { background: var(--bg-card-hover); }
.curriculum-section-header h4 { font-size: 0.95rem; font-weight: 600; }
.curriculum-section-meta { font-size: 0.8rem; color: var(--text-muted); }
.curriculum-section-body { padding: 0.75rem 1.25rem; background: rgba(0,0,0,0.2); }
.curriculum-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.45rem 0;
  font-size: 0.875rem;
  color: var(--text-secondary);
  border-bottom: 1px solid rgba(255,255,255,0.04);
}
.curriculum-item:last-child { border: none; }

/* ---------- Page Banner ---------- */
.page-banner {
  padding: 4.5rem 0 3rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-banner::before {
  content: '';
  position: absolute;
  top: 0; left: 50%;
  transform: translateX(-50%);
  width: 700px; height: 300px;
  background: radial-gradient(ellipse, rgba(6,182,212,0.1), transparent 65%);
  pointer-events: none;
}

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
  justify-content: center;
}
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .sep { opacity: 0.4; }

/* ---------- Tag Pills ---------- */
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 1rem; }
.tag {
  font-size: 0.72rem;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 50px;
  background: var(--accent-dim);
  color: var(--accent);
  border: 1px solid var(--border);
}

/* ---------- Author Card ---------- */
.author-card {
  display: flex;
  gap: 1.25rem;
  align-items: flex-start;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-top: 3rem;
}
.author-avatar {
  width: 64px; height: 64px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--blue));
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
}
.author-info h4 { margin-bottom: 0.25rem; }
.author-info p  { font-size: 0.875rem; margin: 0; }

/* ---------- Newsletter / CTA Strip ---------- */
.cta-strip {
  background: linear-gradient(135deg, rgba(6,182,212,0.12), rgba(59,130,246,0.1));
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 3.5rem;
  text-align: center;
  margin: 3rem 0;
}
.cta-strip h2 { margin-bottom: 0.75rem; }
.cta-strip p  { max-width: 480px; margin: 0 auto 2rem; }

/* ---------- Divider ---------- */
.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 0;
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  section { padding: 3.5rem 0; }
  .hero { padding: 4.5rem 0 4rem; }

  .site-nav { display: none; }
  .menu-toggle { display: flex; }

  .site-nav.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 68px; left: 0; right: 0; bottom: 0;
    background: var(--bg-primary);
    padding: 2rem 1.5rem;
    gap: 1.5rem;
    z-index: 998;
    border-top: 1px solid var(--border);
    overflow-y: auto;
  }
  .nav-link { font-size: 1.1rem; }
  .nav-cta { text-align: center; }

  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 2rem; }

  .hero-stats { gap: 2rem; }
  .article-header { padding: 3rem 0 2rem; }
  .cta-strip { padding: 2.25rem 1.5rem; }
  .author-card { flex-direction: column; }
}

@media (max-width: 480px) {
  .hero-actions { flex-direction: column; align-items: stretch; text-align: center; }
  .btn { justify-content: center; }
  .course-card-footer { flex-direction: column; align-items: flex-start; }
}

/* ---------- Utilities ---------- */
.text-center { text-align: center; }
.text-accent  { color: var(--accent); }
.text-muted   { color: var(--text-muted); }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-4 { margin-bottom: 2rem; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.d-flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.align-center { align-items: center; }
.spacer { flex: 1; }

/* ---------- Glow Dots BG Decoration ---------- */
.bg-dots {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle, rgba(6,182,212,0.06) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
}

/* ---------- Scroll to top ---------- */
#scrollTop {
  position: fixed;
  bottom: 2rem; right: 2rem;
  width: 44px; height: 44px;
  background: var(--accent);
  border-radius: 50%;
  display: none;
  align-items: center; justify-content: center;
  color: #fff;
  font-size: 1.1rem;
  cursor: pointer;
  border: none;
  box-shadow: 0 4px 16px rgba(6,182,212,0.4);
  transition: all var(--transition);
  z-index: 500;
}
#scrollTop:hover { background: var(--accent-bright); transform: translateY(-2px); }
#scrollTop.visible { display: flex; }