/* =======================
   Global Reset & Variables
   ======================= */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary: #1e4e9c;
  --secondary: #337cf2;
  --accent: #00d4ff;
  --text-dark: #1a1a1a;
  --text-light: #6b7280;
  --bg-light: #f8fafc;
  --white: #ffffff;
  --gradient: linear-gradient(
    135deg,
    var(--primary) 0%,
    var(--secondary) 50%,
    var(--accent) 100%
  );
  --shadow: 0 10px 30px rgba(30, 78, 156, 0.1);
  --shadow-hover: 0 20px 40px rgba(30, 78, 156, 0.15);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  line-height: 1.7;
  color: var(--text-dark);
  overflow-x: hidden;
  background: #fff;
}

/* =======================
   Navigation
   ======================= */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  z-index: 1000;
  padding: 1rem 0;
  transition: all 0.3s ease;
  border-bottom: 1px solid rgba(2, 6, 23, 0.04);

  /* Lock navbar typography (prevents subtle shifts) */
  font-size: 1rem; /* 16px baseline */
  line-height: 1.2;
  letter-spacing: 0;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative; /* for mobile dropdown positioning */
}

.logo {
  font-size: 1.5rem; /* consistent logo size */
  font-weight: 700;
  color: var(--text-dark);
  text-decoration: none;
  transition: transform 0.3s ease;
  letter-spacing: 0.2px;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transform-origin: left center;
}

.logo:hover {
  transform: scale(1.05);
}

.logo-accent {
  color: var(--accent);
}

.logo-img {
  display: block;
  height: 28px;
  width: auto;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-dark);
  font-weight: 500;
  transition: color 0.3s ease;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient);
  transition: width 0.3s ease;
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

/* Hamburger toggle (hidden on desktop) */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(2, 6, 23, 0.08);
  border-radius: 10px;
  background: #ffffff;
  cursor: pointer;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.nav-toggle:hover {
  box-shadow: var(--shadow);
  transform: translateY(-1px);
}

.nav-toggle .bar {
  width: 20px;
  height: 2px;
  background: var(--text-dark);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

/* =======================
   Hero Section (Landing)
   ======================= */
.hero {
  min-height: 100vh;
  background: var(--gradient);
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="20" cy="20" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="80" cy="40" r="1" fill="rgba(255,255,255,0.05)"/><circle cx="40" cy="80" r="1" fill="rgba(255,255,255,0.1)"/></pattern></defs><rect width="100%" height="100%" fill="url(%23grain)"/></svg>');
  opacity: 0.3;
}

.hero-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-content h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  color: #fff;
  margin-bottom: 1.5rem;
  line-height: 1.2;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.hero-content .subtitle {
  font-size: 1.25rem;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 2rem;
  font-weight: 300;
}

.cta-section {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(20px);
  padding: 2rem;
  border-radius: 20px;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.cta-section h3 {
  color: #fff;
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.cta-section p {
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: 1.5rem;
}

.email-form {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.email-input {
  flex: 1;
  padding: 1rem 1.5rem;
  border: none;
  border-radius: 50px;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  font-size: 1rem;
  outline: none;
  transition: all 0.3s ease;
}

.email-input:focus {
  background: #fff;
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.3);
}

.notify-btn {
  padding: 1rem 2rem;
  background: var(--white);
  color: var(--primary);
  border: none;
  border-radius: 50px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  white-space: nowrap;
}

.notify-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}

/* Countdown (if used) */
.countdown {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-top: 1rem;
}

.countdown-item {
  text-align: center;
  color: #fff;
}

.countdown-number {
  font-size: 2rem;
  font-weight: 700;
  display: block;
}

.countdown-label {
  font-size: 0.875rem;
  opacity: 0.8;
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* Phone mockup */
.hero-visual {
  position: relative;
  height: 500px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.phone-mockup {
  width: 300px;
  height: 600px;
  background: linear-gradient(145deg, #2a2a2a, #1a1a1a);
  border-radius: 40px;
  padding: 20px;
  box-shadow: 0 30px 60px rgba(0, 0, 0, 0.3);
  position: relative;
  transform: rotate(-5deg);
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%,
  100% {
    transform: rotate(-5deg) translateY(0);
  }
  50% {
    transform: rotate(-5deg) translateY(-20px);
  }
}

.screen {
  width: 100%;
  height: 100%;
  background: var(--gradient);
  border-radius: 25px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  position: relative;
}

.app-interface {
  color: #fff;
  text-align: center;
}

.app-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.app-brand-icon {
  width: 32px;
  height: 32px;
  display: block;
  border-radius: 6px; /* optional */
}

.app-logo {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 2rem;
}

.stat-card {
  background: rgba(255, 255, 255, 0.1);
  padding: 1rem;
  border-radius: 15px;
  text-align: center;
}

.stat-number {
  font-size: 1.5rem;
  font-weight: 700;
}

.stat-label {
  font-size: 0.75rem;
  opacity: 0.8;
}

/* =======================
   Features Section
   ======================= */
.features {
  padding: 6rem 0;
  background: var(--bg-light);
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 800px;
  margin: 0 auto 4rem;
  padding: 0 2rem;
}

.section-header h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  margin-bottom: 1rem;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  color: transparent;
}

.section-header p {
  font-size: 1.125rem;
  color: var(--text-light);
}

.features-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2rem;
}

.feature-card {
  background: #fff;
  padding: 2.5rem;
  border-radius: 20px;
  box-shadow: var(--shadow);
  transition: all 0.3s ease;
  border: 1px solid rgba(30, 78, 156, 0.05);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--gradient);
}

.feature-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-hover);
}

.feature-icon {
  width: 60px;
  height: 60px;
  background: var(--gradient);
  border-radius: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
  color: #fff;
  font-size: 1.5rem;
}

.feature-card h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--text-dark);
}

.feature-list {
  list-style: none;
}

.feature-list li {
  margin-bottom: 0.75rem;
  position: relative;
  padding-left: 1.5rem;
  color: var(--text-light);
}

.feature-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--secondary);
  font-weight: bold;
}

.feature-list li strong {
  color: var(--text-dark);
}

/* =======================
   Newsletter Pages (List & Detail)
   ======================= */

/* Page header banner */
.page-header {
  background: linear-gradient(
    180deg,
    rgba(30, 78, 156, 0.06),
    rgba(0, 212, 255, 0.06)
  );
  padding: 8rem 0 3rem; /* account for fixed navbar */
  border-bottom: 1px solid rgba(30, 78, 156, 0.08);
}

.page-header-content {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 2rem;
  text-align: center;
}

.page-header .header-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 1rem;
  border-radius: 16px;
  background: var(--gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
  font-size: 1.5rem;
}

.page-header h1 {
  font-size: clamp(2rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 0.5rem;
}

.page-header p {
  color: var(--text-light);
  font-size: 1.05rem;
}

/* Main content container */
.main-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 2rem 4rem;
}

/* Grid of newsletter cards */
.newsletters-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}

/* Individual card */
.newsletter-card {
  background: #fff;
  border: 1px solid rgba(30, 78, 156, 0.08);
  border-radius: 16px;
  padding: 1.25rem 1.25rem 1rem;
  box-shadow: var(--shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.newsletter-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.newsletter-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.newsletter-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 44px;
}

.newsletter-info h2 {
  font-size: 1.1rem;
  margin: 0;
}

.newsletter-info a {
  color: var(--text-dark);
  text-decoration: none;
}

.newsletter-info a:hover {
  color: var(--secondary);
}

/* Meta/date and excerpt */
.newsletter-date {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-light);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.newsletter-excerpt {
  color: var(--text-dark);
  opacity: 0.9;
  margin-bottom: 0.75rem;
}

/* Read more button */
.read-more-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: #fff;
  background: var(--gradient);
  padding: 0.55rem 0.9rem;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
}

/* Detail page nav back link */
.back-navigation {
  max-width: 1100px;
  margin: 6rem auto 0; /* space for fixed navbar */
  padding: 0 2rem;
}

.back-link {
  color: var(--secondary);
  text-decoration: none;
  font-weight: 600;
}

.back-link:hover {
  text-decoration: underline;
}

/* Detail header, meta, tags */
.newsletter-header h1 {
  margin-top: 0.5rem;
}

.newsletter-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  margin-top: 0.5rem;
  color: var(--text-light);
}

.newsletter-meta .meta-item {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.newsletter-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

.newsletter-tags .tag {
  font-size: 0.85rem;
  padding: 0.3rem 0.6rem;
  background: rgba(51, 124, 242, 0.1);
  color: var(--secondary);
  border: 1px solid rgba(51, 124, 242, 0.2);
  border-radius: 999px;
}

/* Detail content */
.newsletter-content {
  margin-top: 1.25rem;
  background: #fff;
  border: 1px solid rgba(30, 78, 156, 0.08);
  border-radius: 16px;
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

.newsletter-content h2,
.newsletter-content h3 {
  margin-top: 1rem;
  margin-bottom: 0.5rem;
}

.newsletter-content p,
.newsletter-content li {
  color: var(--text-dark);
}

.newsletter-content ul {
  padding-left: 1.25rem;
}

.newsletter-content blockquote {
  margin: 1rem 0;
  padding: 1rem 1.25rem;
  background: rgba(0, 212, 255, 0.08);
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  color: var(--text-dark);
}

/* Actions */
.newsletter-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1rem;
}

.action-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  border-radius: 10px;
  padding: 0.6rem 1rem;
  cursor: pointer;
  border: none;
  text-decoration: none;
  font-weight: 600;
}

.action-btn.primary {
  background: var(--gradient);
  color: #fff;
}

.action-btn.secondary {
  background: #f1f5f9;
  color: var(--text-dark);
}

/* =======================
   Footer
   ======================= */
.footer {
  background: var(--text-dark);
  color: #fff;
  text-align: center;
  padding: 2rem 0;
}

/* =======================
   Responsive
   ======================= */
@media (max-width: 1024px) {
  .hero-container {
    gap: 3rem;
  }
}

@media (max-width: 768px) {
  .nav-container {
    padding: 0 1rem;
  }

  /* Show hamburger, convert links to dropdown */
  .nav-toggle {
    display: inline-flex;
  }

  .nav-links {
    position: absolute;
    top: 64px; /* below navbar */
    left: 16px;
    right: 16px;
    display: none; /* hidden until opened */
    flex-direction: column;
    gap: 0;
    list-style: none;
    background: #ffffff;
    border: 1px solid rgba(2, 6, 23, 0.08);
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 8px;
    z-index: 1001;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    width: 100%;
  }

  .nav-links a {
    display: block;
    width: 100%;
    padding: 12px 14px;
    border-radius: 8px;
  }

  .nav-links a:hover {
    background: #f8fafc;
  }

  /* Remove desktop underline animation on mobile */
  .nav-links a::after {
    display: none;
    content: none;
  }

  /* Animate hamburger to X when active */
  .nav-toggle.active .bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  .nav-toggle.active .bar:nth-child(2) {
    opacity: 0;
  }
  .nav-toggle.active .bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .hero-container {
    grid-template-columns: 1fr;
    gap: 2rem;
    text-align: center;
  }

  .hero-visual {
    order: -1;
    height: 300px;
  }

  .phone-mockup {
    width: 200px;
    height: 400px;
  }

  .email-form {
    flex-direction: column;
  }

  .countdown {
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
  }

  .features-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .feature-card {
    padding: 2rem;
  }

  /* Newsletter pages */
  .page-header {
    padding: 7rem 0 2rem;
  }

  .main-content {
    padding: 1.25rem 1rem 3rem;
  }
}

@media (max-width: 480px) {
  .cta-section {
    padding: 1.5rem;
    margin: 0 1rem;
  }

  .features-container {
    padding: 0 1rem;
  }
}

/* =======================
   Hard Guards for Navbar
   ======================= */

/* Ensure navbar logo colors are always visible on white background */
.navbar .logo {
  color: var(--text-dark) !important;
}
.navbar .logo .logo-accent {
  color: var(--accent) !important;
}

/* Prevent content typography from leaking into the navbar */
.navbar,
.navbar * {
  text-transform: none;
  letter-spacing: normal;
  line-height: normal;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif !important;
}

/* =======================
   Article layout for newsletter detail
   ======================= */
.article-wrap {
  max-width: 1200px;
  margin: 6rem auto 3rem;
  padding: 0 2rem;
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 2rem;
}

.article-aside {
  position: sticky;
  top: 84px; /* below fixed navbar */
  align-self: start;
}

.article-meta {
  background: #fff;
  border: 1px solid rgba(30, 78, 156, 0.08);
  border-radius: 16px;
  padding: 1rem;
  box-shadow: var(--shadow);
  margin-top: 0.75rem;
}

.article-title {
  font-size: 1.1rem;
  margin: 0 0 0.5rem 0;
}

.meta-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-light);
  font-size: 0.95rem;
  margin: 0.25rem 0;
}

.article-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.5rem;
}
.article-tags .tag {
  font-size: 0.8rem;
  padding: 0.25rem 0.5rem;
  background: rgba(51, 124, 242, 0.08);
  color: var(--secondary);
  border: 1px solid rgba(51, 124, 242, 0.2);
  border-radius: 999px;
}

.toc {
  margin-top: 1rem;
  background: #fff;
  border: 1px solid rgba(30, 78, 156, 0.08);
  border-radius: 16px;
  padding: 0.75rem 0.75rem 0.75rem 1rem;
  box-shadow: var(--shadow);
}
.toc-title {
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text-dark);
}
#toc-list {
  list-style: none;
  padding-left: 0;
}
#toc-list li {
  margin: 0.25rem 0;
}
#toc-list a {
  text-decoration: none;
  color: var(--text-dark);
  font-size: 0.95rem;
}
#toc-list a:hover {
  color: var(--secondary);
}
.toc-h3 {
  margin-left: 0.75rem;
  opacity: 0.9;
}

.article-main .article-hero {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}
.article-hero .newsletter-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--gradient);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

@media (max-width: 992px) {
  .article-wrap {
    grid-template-columns: 1fr;
  }
  .article-aside {
    position: static;
  }
}