/* ==========================================================================
   The Sentinel Protocols — Series Website
   Dark techno-thriller aesthetic: navy/black, electric blue accents
   ========================================================================== */

/* --- Google Fonts (Rajdhani for headers, Inter for body) --- */
@import url('https://fonts.googleapis.com/css2?family=Rajdhani:wght@400;500;600;700&family=Inter:wght@300;400;500;600&display=swap');

/* --- CSS Custom Properties --- */
:root {
  --color-bg:            #0a0e1a;
  --color-bg-alt:        #0f1424;
  --color-bg-card:       #131830;
  --color-bg-card-hover: #1a2040;
  --color-surface:       #1a2332;
  --color-border:        #1e2a3a;
  --color-text:          #e0e6ed;
  --color-text-muted:    #8899aa;
  --color-text-dim:      #556677;
  --color-accent:        #00b4d8;
  --color-accent-hover:  #00cfff;
  --color-accent-glow:   rgba(0, 180, 216, 0.15);
  --color-amber:         #ff6b1a;
  --color-error:         #ff4757;
  --color-success:       #2ed573;
  --font-heading:        'Rajdhani', 'Eurostile', sans-serif;
  --font-body:           'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --max-width:           1200px;
  --max-width-narrow:    800px;
  --transition:          0.25s ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-accent-hover);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

h1, h2, h3, h4, h5 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: 0.02em;
}

/* --- Utility --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.container--narrow {
  max-width: var(--max-width-narrow);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.text-accent { color: var(--color-accent); }
.text-muted  { color: var(--color-text-muted); }
.text-center { text-align: center; }

/* ==========================================================================
   HEADER & NAVIGATION
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 14, 26, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 72px;
}

.site-logo {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-text);
  text-decoration: none;
}

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

.site-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.site-nav__link {
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.9rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
  position: relative;
}

.site-nav__link:hover,
.site-nav__link--active {
  color: var(--color-accent);
}

.site-nav__link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-accent);
  transform: scaleX(0);
  transition: transform var(--transition);
}

.site-nav__link:hover::after,
.site-nav__link--active::after {
  transform: scaleX(1);
}

/* Mobile hamburger */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle__bar {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  margin: 5px 0;
  transition: all var(--transition);
}

.nav-toggle.active .nav-toggle__bar:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.nav-toggle.active .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle.active .nav-toggle__bar:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 120px 24px 80px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 30% 20%, rgba(0, 180, 216, 0.06) 0%, transparent 60%),
    radial-gradient(ellipse at 70% 80%, rgba(255, 107, 26, 0.04) 0%, transparent 60%);
  pointer-events: none;
}

/* Animated grid lines background */
.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(0, 180, 216, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 180, 216, 0.03) 1px, transparent 1px);
  background-size: 80px 80px;
  pointer-events: none;
}

.hero__content {
  text-align: center;
  max-width: 900px;
  position: relative;
  z-index: 1;
}

.hero__series-tag {
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.85rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 16px;
  display: block;
}

.hero__title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 700;
  color: #fff;
  margin-bottom: 24px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.hero__tagline {
  font-size: clamp(1.1rem, 2.5vw, 1.5rem);
  color: var(--color-text-muted);
  font-weight: 300;
  margin-bottom: 40px;
  max-width: 650px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.5;
}

.hero__tagline em {
  color: var(--color-amber);
  font-style: normal;
  font-weight: 500;
}

.hero__cta-group {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ==========================================================================
   BUTTONS
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 14px 32px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}

.btn--primary {
  background: var(--color-accent);
  color: var(--color-bg);
}

.btn--primary:hover {
  background: var(--color-accent-hover);
  color: var(--color-bg);
  box-shadow: 0 0 24px rgba(0, 180, 216, 0.3);
}

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

.btn--outline:hover {
  background: var(--color-accent-glow);
  color: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
}

.btn--small {
  padding: 10px 24px;
  font-size: 0.85rem;
}

/* ==========================================================================
   SECTIONS
   ========================================================================== */
section {
  padding: 100px 0;
}

.section-divider {
  width: 60px;
  height: 2px;
  background: var(--color-accent);
  margin: 0 auto 48px;
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  text-align: center;
  margin-bottom: 16px;
  color: #fff;
}

.section-subtitle {
  text-align: center;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto 60px;
  font-size: 1rem;
}

/* ==========================================================================
   BOOK FEATURE SECTION
   ========================================================================== */
.book-feature {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.book-feature__grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 60px;
  align-items: center;
}

.book-cover {
  position: relative;
}

.book-cover__image {
  border-radius: 4px;
  box-shadow:
    0 20px 60px rgba(0, 0, 0, 0.5),
    0 0 40px rgba(0, 180, 216, 0.08);
  transition: transform var(--transition), box-shadow var(--transition);
}

.book-cover:hover .book-cover__image {
  transform: translateY(-4px);
  box-shadow:
    0 24px 70px rgba(0, 0, 0, 0.6),
    0 0 50px rgba(0, 180, 216, 0.12);
}

.book-cover__badge {
  position: absolute;
  top: -12px;
  right: -12px;
  background: var(--color-amber);
  color: var(--color-bg);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 8px 16px;
  border-radius: 4px;
}

.book-details__series {
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.85rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.book-details__title {
  font-size: clamp(2rem, 4vw, 3rem);
  color: #fff;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.book-details__author {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin-bottom: 24px;
}

.book-details__blurb {
  font-size: 1.05rem;
  line-height: 1.8;
  margin-bottom: 24px;
  color: var(--color-text);
}

.book-details__quote {
  border-left: 3px solid var(--color-accent);
  padding-left: 20px;
  margin: 32px 0;
  font-style: italic;
  color: var(--color-text-muted);
  font-size: 1.05rem;
  line-height: 1.6;
}

.book-details__meta {
  display: flex;
  gap: 24px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}

.book-details__meta-item {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.book-details__meta-item strong {
  color: var(--color-text);
  display: block;
  margin-bottom: 2px;
}

.book-details__buy-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* ==========================================================================
   SIGNUP / NEWSLETTER
   ========================================================================== */
.signup-section {
  background: var(--color-bg);
  position: relative;
}

.signup-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, rgba(0, 180, 216, 0.04) 0%, transparent 70%);
  pointer-events: none;
}

.signup-box {
  max-width: 560px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 1;
}

.signup-box__title {
  font-size: 1.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 16px;
  color: #fff;
}

.signup-box__text {
  color: var(--color-text-muted);
  margin-bottom: 32px;
  line-height: 1.6;
}

.signup-form {
  display: flex;
  gap: 12px;
  max-width: 480px;
  margin: 0 auto;
}

.signup-form__input {
  flex: 1;
  padding: 14px 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition);
}

.signup-form__input::placeholder {
  color: var(--color-text-dim);
}

.signup-form__input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.signup-form__status {
  margin-top: 16px;
  font-size: 0.9rem;
  min-height: 24px;
}

.signup-form__status--success {
  color: var(--color-success);
}

.signup-form__status--error {
  color: var(--color-error);
}

.signup-form__privacy {
  margin-top: 12px;
  font-size: 0.75rem;
  color: var(--color-text-dim);
}

/* ==========================================================================
   AUTHOR SECTION
   ========================================================================== */
.author-section {
  border-top: 1px solid var(--color-border);
}

.author-grid {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 48px;
  align-items: start;
}

.author-photo {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--color-border);
}

.author-bio__name {
  font-size: 1.6rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #fff;
  margin-bottom: 8px;
}

.author-bio__credentials {
  font-size: 0.9rem;
  color: var(--color-accent);
  margin-bottom: 20px;
  font-family: var(--font-heading);
  letter-spacing: 0.05em;
}

.author-bio__text {
  color: var(--color-text);
  line-height: 1.8;
  margin-bottom: 16px;
}

.author-bio__text:last-of-type {
  margin-bottom: 24px;
}

/* ==========================================================================
   BOOKS GRID (Books page)
   ========================================================================== */
.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 32px;
  margin-top: 48px;
}

.book-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 24px;
  text-align: center;
  transition: all var(--transition);
}

.book-card:hover {
  background: var(--color-bg-card-hover);
  border-color: rgba(0, 180, 216, 0.2);
  transform: translateY(-2px);
}

.book-card--featured {
  grid-column: span 2;
  grid-row: span 2;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  text-align: left;
  align-items: center;
}

.book-card__number {
  font-family: var(--font-heading);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.book-card__title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  color: #fff;
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.book-card__status {
  font-size: 0.8rem;
  color: var(--color-text-dim);
  font-family: var(--font-heading);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.book-card__status--available {
  color: var(--color-accent);
}

.book-card__cover {
  max-height: 300px;
  margin: 0 auto 16px;
  border-radius: 3px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

/* ==========================================================================
   PRESS KIT
   ========================================================================== */
.press-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  margin-top: 48px;
}

.press-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 32px;
}

.press-card__title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent);
  margin-bottom: 16px;
}

.press-card__text {
  color: var(--color-text);
  line-height: 1.7;
  margin-bottom: 12px;
}

.press-card__text:last-child {
  margin-bottom: 0;
}

.press-assets {
  list-style: none;
}

.press-assets li {
  padding: 12px 0;
  border-bottom: 1px solid var(--color-border);
}

.press-assets li:last-child {
  border-bottom: none;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.site-footer {
  margin-top: auto;
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding: 48px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand__name {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text);
  margin-bottom: 12px;
}

.footer-brand__text {
  color: var(--color-text-dim);
  font-size: 0.85rem;
  line-height: 1.6;
  max-width: 320px;
}

.footer-links__title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.85rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 16px;
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  color: var(--color-text-dim);
  font-size: 0.9rem;
  transition: color var(--transition);
}

.footer-links a:hover {
  color: var(--color-accent);
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--color-text-dim);
}

/* ==========================================================================
   PAGE-SPECIFIC: Newsletter
   ========================================================================== */
.newsletter-hero {
  padding: 160px 24px 80px;
  text-align: center;
}

.newsletter-hero__title {
  font-size: clamp(2rem, 4vw, 3rem);
  text-transform: uppercase;
  color: #fff;
  margin-bottom: 24px;
}

.newsletter-hero__text {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto 40px;
  line-height: 1.7;
}

.newsletter-benefits {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  max-width: 800px;
  margin: 60px auto 0;
}

.newsletter-benefit {
  text-align: center;
  padding: 24px;
}

.newsletter-benefit__icon {
  font-size: 2rem;
  margin-bottom: 12px;
  color: var(--color-accent);
}

.newsletter-benefit__title {
  font-family: var(--font-heading);
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #fff;
  margin-bottom: 8px;
}

.newsletter-benefit__text {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ==========================================================================
   PAGE-SPECIFIC: 404
   ========================================================================== */
.error-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px;
}

.error-page__code {
  font-family: var(--font-heading);
  font-size: clamp(6rem, 15vw, 12rem);
  font-weight: 700;
  color: var(--color-surface);
  line-height: 1;
  margin-bottom: 16px;
}

.error-page__title {
  font-size: 1.5rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 24px;
}

.error-page__text {
  color: var(--color-text-dim);
  margin-bottom: 32px;
}

/* ==========================================================================
   PAGE HEADER (non-hero pages)
   ========================================================================== */
.page-header {
  padding: 140px 24px 60px;
  text-align: center;
  border-bottom: 1px solid var(--color-border);
}

.page-header__title {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #fff;
  margin-bottom: 16px;
}

.page-header__subtitle {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  max-width: 600px;
  margin: 0 auto;
}

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .site-nav {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: rgba(10, 14, 26, 0.98);
    backdrop-filter: blur(16px);
    flex-direction: column;
    padding: 32px 24px;
    gap: 24px;
    border-bottom: 1px solid var(--color-border);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition), opacity var(--transition);
  }

  .site-nav.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .hero {
    min-height: 90vh;
    padding: 100px 24px 60px;
  }

  .book-feature__grid {
    grid-template-columns: 1fr;
    gap: 40px;
    text-align: center;
  }

  .book-cover__image {
    max-width: 280px;
    margin: 0 auto;
  }

  .book-details__meta {
    justify-content: center;
  }

  .book-details__buy-links {
    justify-content: center;
  }

  .author-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .author-photo {
    margin: 0 auto;
  }

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

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }

  .press-grid {
    grid-template-columns: 1fr;
  }

  .book-card--featured {
    grid-column: span 1;
    grid-row: span 1;
    grid-template-columns: 1fr;
  }

  .newsletter-benefits {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .books-grid {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
  }
}

@media (max-width: 480px) {
  .hero__cta-group {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    max-width: 300px;
  }

  section {
    padding: 60px 0;
  }
}