/* ============================================
   SkyBook – Air Ticketing Template
   Static HTML/CSS/JS. No frameworks.
   API integration points noted in HTML/JS.
   ============================================ */

:root {
  /* Travel-oriented color scheme: deep blue, teal, warm accent */
  --color-primary: #0d47a1;
  --color-primary-dark: #002171;
  --color-primary-light: #5472d3;
  --color-accent: #ff6f00;
  --color-accent-hover: #e65100;
  --color-teal: #00695c;
  --color-teal-light: #00897b;
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --color-success: #2e7d32;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --radius: 8px;
  --radius-lg: 12px;
  --font-sans: 'Outfit', 'DM Sans', system-ui, sans-serif;
  --transition: 0.2s ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover {
  color: var(--color-primary-dark);
}

/* ---------- Layout ---------- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

@media (min-width: 768px) {
  .container {
    padding: 0 1.5rem;
  }
}

/* ========== HEADER ========== */
.site-header {
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  font-weight: 700;
  font-size: 1.35rem;
  color: var(--color-primary);
}
.logo:hover {
  color: var(--color-primary-dark);
}

.logo-text {
  /* Placeholder: replace with <img src="images/logo.png" alt="SkyBook"> when asset ready */
  letter-spacing: -0.02em;
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  background: none;
  border: none;
  cursor: pointer;
  border-radius: var(--radius);
}
.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 1px;
  transition: var(--transition);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}
@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }
}

.main-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0;
}
@media (min-width: 768px) {
  .main-nav ul {
    flex-direction: row;
    gap: 0.5rem;
  }
}

.main-nav a {
  display: block;
  padding: 0.75rem 1rem;
  color: var(--color-text);
  font-weight: 500;
  border-radius: var(--radius);
}
.main-nav a:hover,
.main-nav a.active {
  color: var(--color-primary);
  background: rgba(13, 71, 161, 0.08);
}

@media (max-width: 767px) {
  .main-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    box-shadow: var(--shadow-lg);
    padding: 0.5rem;
    display: none;
  }
  .main-nav.is-open {
    display: block;
  }
}

/* ========== BUTTONS ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.625rem 1.25rem;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
}
.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}
.btn:hover {
  transform: translateY(-1px);
}
.btn:active {
  transform: translateY(0);
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}
.btn-primary:hover {
  background: var(--color-accent-hover);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}
.btn-outline:hover {
  background: var(--color-primary);
  color: #fff;
}

.btn-search {
  padding: 0.875rem 2rem;
  font-size: 1.05rem;
  min-width: 180px;
}

/* ========== HERO + SEARCH FORM ========== */
.hero {
  position: relative;
  padding: 2.5rem 0 3.5rem;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 50%, #001a4d 100%);
  z-index: 0;
}
.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.04'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.5;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  color: #fff;
  text-align: center;
}

.hero-subtitle {
  margin: 0 0 2rem;
  color: rgba(255, 255, 255, 0.9);
  text-align: center;
  font-size: 1.05rem;
}

/* Search form */
.search-form {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 1.5rem;
  max-width: 900px;
  margin: 0 auto;
}

.form-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
}
.form-row:last-of-type {
  margin-bottom: 1.25rem;
}

.form-row-main {
  align-items: flex-end;
}

.form-group {
  flex: 1 1 140px;
  min-width: 0;
}

.form-group label {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 0.625rem 0.875rem;
  font-family: inherit;
  font-size: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color var(--transition), box-shadow var(--transition);
}
.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(13, 71, 161, 0.15);
}
.form-group input::placeholder {
  color: var(--color-text-muted);
}

.swap-btn {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  color: var(--color-text-muted);
  transition: background var(--transition), color var(--transition);
  align-self: flex-end;
  margin-bottom: 0.25rem;
}
.swap-btn:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.form-actions {
  display: flex;
  justify-content: center;
  margin-top: 0.5rem;
}

@media (min-width: 640px) {
  .form-row-main .form-group {
    flex: 1 1 180px;
  }
  .form-row .form-group {
    flex: 1 1 160px;
  }
}

@media (min-width: 768px) {
  .search-form {
    padding: 2rem;
  }
  .form-row-main {
    margin-bottom: 1.25rem;
  }
}

/* ========== SECTIONS ========== */
.section-title {
  margin: 0 0 1.5rem;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  text-align: center;
}

.promo-section {
  padding: 3rem 0;
}

.promo-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}
@media (min-width: 640px) {
  .promo-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (min-width: 900px) {
  .promo-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.promo-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition);
}
.promo-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.promo-image {
  height: 140px;
  /* Placeholder gradient; replace with background-image when assets ready */
}

.promo-content {
  padding: 1.25rem;
}
.promo-content h3 {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
}
.promo-content p {
  margin: 0 0 0.75rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.link-arrow {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}
.link-arrow:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* Services */
.services-section {
  padding: 3rem 0 4rem;
  background: var(--color-surface);
}

.services-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}
@media (min-width: 640px) {
  .services-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.service-card {
  text-align: center;
  padding: 2rem 1.5rem;
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  transition: border-color var(--transition), box-shadow var(--transition);
}
.service-card:hover {
  border-color: var(--color-primary-light);
  box-shadow: var(--shadow-md);
}

.service-icon {
  margin: 0 auto 1rem;
  color: var(--color-primary);
}
.service-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.15rem;
  font-weight: 600;
}
.service-card p {
  margin: 0 0 1.25rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ========== FOOTER ========== */
.site-footer {
  background: var(--color-primary-dark);
  color: rgba(255, 255, 255, 0.9);
  padding: 2.5rem 0 1.5rem;
}

.footer-inner a {
  color: rgba(255, 255, 255, 0.85);
}
.footer-inner a:hover {
  color: #fff;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}
@media (min-width: 640px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}
@media (min-width: 900px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

.footer-brand .logo-text {
  font-weight: 700;
  font-size: 1.25rem;
  color: #fff;
  display: block;
  margin-bottom: 0.5rem;
}
.footer-brand p {
  margin: 0;
  font-size: 0.9rem;
  opacity: 0.85;
}

.footer-links h4,
.footer-contact h4,
.footer-social h4 {
  margin: 0 0 0.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: #fff;
}

.footer-links ul {
  list-style: none;
  margin: 0;
  padding: 0;
}
.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-contact p,
.footer-social p {
  margin: 0 0 0.5rem;
  font-size: 0.9rem;
}

.social-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 0.75rem;
}
.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: var(--radius);
  transition: background var(--transition);
}
.social-links a:hover {
  background: var(--color-accent);
  color: #fff;
}

.footer-bottom {
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.15);
  text-align: center;
}
.footer-bottom p {
  margin: 0;
  font-size: 0.85rem;
  opacity: 0.8;
}

/* ========== FLIGHTS PAGE ========== */
.flights-page {
  padding-bottom: 3rem;
}

.search-summary {
  background: var(--color-surface);
  padding: 1.25rem 0;
  box-shadow: var(--shadow-sm);
}

.summary-content h1 {
  margin: 0 0 0.25rem;
  font-size: 1.35rem;
  font-weight: 700;
}
.summary-dates {
  margin: 0 0 0.5rem;
  font-size: 0.95rem;
  color: var(--color-text-muted);
}
.summary-content .link-arrow {
  font-size: 0.9rem;
}

.flights-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  padding-top: 1.5rem;
}
@media (min-width: 900px) {
  .flights-layout {
    grid-template-columns: 260px 1fr;
    align-items: start;
  }
}

/* Filters sidebar */
.filters-sidebar {
  position: sticky;
  top: 80px;
}

.filters-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
}

.filters-card h3 {
  margin: 0 0 1rem;
  font-size: 1.1rem;
  font-weight: 600;
}

.filter-group {
  margin-bottom: 1.25rem;
}
.filter-group:last-child {
  margin-bottom: 0;
}

.filter-group > label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.filter-options {
  list-style: none;
  margin: 0;
  padding: 0;
}
.filter-options li {
  margin-bottom: 0.35rem;
}
.filter-options label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  cursor: pointer;
  font-weight: 400;
}
.filter-options input[type="radio"],
.filter-options input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  accent-color: var(--color-primary);
}

.price-range {
  padding-top: 0.25rem;
}
.price-range input[type="range"] {
  width: 100%;
  margin-bottom: 0.5rem;
  accent-color: var(--color-primary);
}
.price-range-label {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

/* Toolbar */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.results-count {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.sort-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.sort-controls label {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
.sort-controls select {
  padding: 0.5rem 0.75rem;
  font-family: inherit;
  font-size: 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  cursor: pointer;
}

/* Flight list */
.flight-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.flight-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: box-shadow var(--transition), border-color var(--transition);
}
.flight-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-light);
}

.flight-card-main {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  padding: 1.25rem;
}
@media (min-width: 768px) {
  .flight-card-main {
    grid-template-columns: 1.5fr 2fr 1fr;
    align-items: center;
    padding: 1.5rem;
  }
}

.flight-airline {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.airline-logo {
  width: 48px;
  height: 48px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  /* Placeholder: use <img src="images/airline-{code}.png" alt=""> when logos available */
}

.airline-initial {
  font-size: 0.75rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.02em;
}

.airline-info {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.airline-name {
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text);
}
.flight-number {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.flight-times {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.time-block {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.time-block .time {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
}
.time-block .city {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.flight-duration {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex: 1;
  min-width: 80px;
}
.duration {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  white-space: nowrap;
}
.route-line {
  flex: 1;
  height: 1px;
  background: var(--color-border);
  min-width: 20px;
}

.flight-price-action {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: flex-start;
}
@media (min-width: 768px) {
  .flight-price-action {
    flex-direction: column;
    align-items: flex-end;
    justify-content: center;
  }
}

.price-block {
  text-align: left;
}
@media (min-width: 768px) {
  .price-block {
    text-align: right;
  }
}
.price-block .price {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-primary);
  display: block;
}
.price-note {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.btn-book {
  width: 100%;
}
@media (min-width: 768px) {
  .btn-book {
    width: auto;
    min-width: 120px;
  }
}

/* Mobile: stack flight card content clearly */
@media (max-width: 767px) {
  .flight-card-main {
    grid-template-columns: 1fr;
  }
  .flight-times {
    padding-left: 0;
  }
  .flight-price-action {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    width: 100%;
  }
  .btn-book {
    flex-shrink: 0;
  }
}