/* ============================================================================
   Stratus Sovereign - Global Air Concierge
   航太工業美學設計系統 (Aerospace Minimalism)
   
   核心色系：
   - 深邃平流層藍 (#0A192F)：主背景色，象徵萬米高空的靜謐與安全
   - 鈦金屬冷銀 (#B4BEC9)：強調色，用於機身細節與數據邊框
   - 航跡破曉金 (#D4AF37)：用於核心按鈕與尊榮會員標誌
   ============================================================================ */

/* ============================================================================
   1. 全局重置與基礎設定
   ============================================================================ */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: #0A192F;
  color: #E8E8E8;
  line-height: 1.6;
  overflow-x: hidden;
}

/* ============================================================================
   2. 排版系統
   ============================================================================ */

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  letter-spacing: -0.5px;
  color: #FFFFFF;
}

h1 {
  font-size: 3.5rem;
  line-height: 1.1;
  margin-bottom: 1.5rem;
}

h2 {
  font-size: 2.5rem;
  line-height: 1.2;
  margin-bottom: 1.5rem;
}

h3 {
  font-size: 1.8rem;
  line-height: 1.3;
  margin-bottom: 1rem;
}

h4 {
  font-size: 1.4rem;
  margin-bottom: 0.8rem;
}

p {
  font-size: 1rem;
  margin-bottom: 1rem;
  color: #D0D0D0;
}

a {
  color: #D4AF37;
  text-decoration: none;
  transition: all 0.3s ease;
}

a:hover {
  color: #E8C547;
  text-shadow: 0 0 10px rgba(212, 175, 55, 0.3);
}

/* ============================================================================
   3. 導航欄
   ============================================================================ */

nav {
  background: linear-gradient(135deg, #0A192F 0%, #0F2847 100%);
  padding: 1.5rem 0;
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid rgba(180, 190, 201, 0.2);
  backdrop-filter: blur(10px);
}

nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
}

nav .logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: #D4AF37;
  letter-spacing: 2px;
  text-transform: uppercase;
}

nav .nav-links {
  display: flex;
  list-style: none;
  gap: 2.5rem;
  align-items: center;
}

nav .nav-links a {
  color: #B4BEC9;
  font-size: 0.95rem;
  font-weight: 500;
  position: relative;
  transition: all 0.3s ease;
}

nav .nav-links a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, #D4AF37, transparent);
  transition: width 0.3s ease;
}

nav .nav-links a:hover {
  color: #D4AF37;
}

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

nav .nav-links a.active {
  color: #D4AF37;
}

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

/* ============================================================================
   4. 容器與佈局
   ============================================================================ */

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
}

body > main {
  margin-top: 80px;
}

section {
  padding: 5rem 0;
}

/* ============================================================================
   5. Hero Section 樣式
   ============================================================================ */

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #0A192F 0%, #0F2847 50%, #1A3A52 100%);
  overflow: hidden;
  margin-top: 80px;
}

.hero::before {
  content: '';
  position: absolute;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(212, 175, 55, 0.1) 0%, transparent 70%);
  border-radius: 50%;
  top: 20%;
  right: 10%;
  animation: pulse 4s ease-in-out infinite;
}

.hero::after {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(180, 190, 201, 0.05) 0%, transparent 70%);
  border-radius: 50%;
  bottom: 10%;
  left: 5%;
  animation: pulse 5s ease-in-out infinite 1s;
}

.hero-content {
  position: relative;
  z-index: 10;
  text-align: center;
  max-width: 900px;
}

.hero h1 {
  font-size: 4.5rem;
  margin-bottom: 1.5rem;
  background: linear-gradient(135deg, #FFFFFF 0%, #D4AF37 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: fadeInDown 1s ease;
}

.hero .subtitle {
  font-size: 1.3rem;
  color: #B4BEC9;
  margin-bottom: 2rem;
  animation: fadeInUp 1s ease 0.2s both;
}

.hero .tagline {
  font-size: 1.1rem;
  color: #D4AF37;
  font-style: italic;
  margin-bottom: 2rem;
  animation: fadeInUp 1s ease 0.4s both;
}

.hero-buttons {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInUp 1s ease 0.6s both;
}

/* ============================================================================
   6. 按鈕樣式
   ============================================================================ */

.btn {
  padding: 0.9rem 2rem;
  border: none;
  border-radius: 4px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.1);
  transition: left 0.3s ease;
  z-index: -1;
}

.btn:hover::before {
  left: 0;
}

.btn-primary {
  background: linear-gradient(135deg, #D4AF37 0%, #E8C547 100%);
  color: #0A192F;
  border: 2px solid #D4AF37;
  box-shadow: 0 8px 24px rgba(212, 175, 55, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(212, 175, 55, 0.5);
}

.btn-secondary {
  background: transparent;
  color: #B4BEC9;
  border: 2px solid #B4BEC9;
}

.btn-secondary:hover {
  background: rgba(180, 190, 201, 0.1);
  color: #D4AF37;
  border-color: #D4AF37;
}

.btn-small {
  padding: 0.6rem 1.2rem;
  font-size: 0.85rem;
}

/* ============================================================================
   7. 卡片與容器
   ============================================================================ */

.card {
  background: rgba(15, 40, 71, 0.6);
  border: 1px solid rgba(180, 190, 201, 0.2);
  border-radius: 8px;
  padding: 2rem;
  backdrop-filter: blur(10px);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, #D4AF37, transparent);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.card:hover {
  border-color: rgba(212, 175, 55, 0.4);
  background: rgba(15, 40, 71, 0.8);
  transform: translateY(-5px);
  box-shadow: 0 12px 40px rgba(212, 175, 55, 0.15);
}

.card:hover::before {
  opacity: 1;
}

.card h3 {
  color: #D4AF37;
  margin-bottom: 1rem;
}

.card p {
  color: #B4BEC9;
  font-size: 0.95rem;
}

/* ============================================================================
   8. 網格佈局
   ============================================================================ */

.grid {
  display: grid;
  gap: 2rem;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* ============================================================================
   9. 動畫效果
   ============================================================================ */

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 0.5;
  }
  50% {
    transform: scale(1.1);
    opacity: 0.8;
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes glow {
  0%, 100% {
    box-shadow: 0 0 10px rgba(212, 175, 55, 0.3);
  }
  50% {
    box-shadow: 0 0 20px rgba(212, 175, 55, 0.6);
  }
}

@keyframes scanline {
  0% {
    transform: translateY(-100%);
  }
  100% {
    transform: translateY(100%);
  }
}

@keyframes hudPulse {
  0%, 100% {
    opacity: 0.5;
  }
  50% {
    opacity: 1;
  }
}

/* ============================================================================
   10. HUD 飛行數據 UI 效果
   ============================================================================ */

.hud-card {
  position: relative;
  background: rgba(10, 25, 47, 0.8);
  border: 2px solid #B4BEC9;
  border-radius: 0;
  padding: 1.5rem;
  transition: all 0.3s ease;
}

.hud-card::before {
  content: '';
  position: absolute;
  top: -10px;
  left: -10px;
  right: -10px;
  bottom: -10px;
  border: 1px solid rgba(212, 175, 55, 0.3);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.hud-card:hover::before {
  opacity: 1;
  animation: glow 1s ease infinite;
}

.hud-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(90deg, transparent, rgba(212, 175, 55, 0.1), transparent);
  opacity: 0;
  animation: scanline 3s linear infinite;
  pointer-events: none;
}

.hud-card:hover::after {
  opacity: 1;
}

.hud-label {
  font-size: 0.75rem;
  color: #B4BEC9;
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 0.5rem;
  opacity: 0.7;
}

.hud-value {
  font-size: 1.5rem;
  color: #D4AF37;
  font-weight: 700;
  font-family: 'Courier New', monospace;
}

/* ============================================================================
   11. 表單樣式
   ============================================================================ */

.form-group {
  margin-bottom: 1.5rem;
}

label {
  display: block;
  margin-bottom: 0.5rem;
  color: #B4BEC9;
  font-size: 0.95rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
}

input, select, textarea {
  width: 100%;
  padding: 0.9rem;
  background: rgba(15, 40, 71, 0.6);
  border: 1px solid rgba(180, 190, 201, 0.3);
  border-radius: 4px;
  color: #E8E8E8;
  font-size: 1rem;
  transition: all 0.3s ease;
  font-family: inherit;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: #D4AF37;
  background: rgba(15, 40, 71, 0.8);
  box-shadow: 0 0 20px rgba(212, 175, 55, 0.2);
}

textarea {
  resize: vertical;
  min-height: 120px;
}

/* ============================================================================
   12. 頁尾
   ============================================================================ */

footer {
  background: linear-gradient(135deg, #0A192F 0%, #0F2847 100%);
  border-top: 1px solid rgba(180, 190, 201, 0.2);
  padding: 3rem 0 1rem;
  margin-top: 5rem;
}

footer .footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

footer h4 {
  color: #D4AF37;
  margin-bottom: 1rem;
}

footer p, footer a {
  color: #B4BEC9;
  font-size: 0.9rem;
}

footer a:hover {
  color: #D4AF37;
}

footer .footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid rgba(180, 190, 201, 0.1);
  color: #7A8A9A;
  font-size: 0.85rem;
}

/* ============================================================================
   13. 響應式設計
   ============================================================================ */

@media (max-width: 768px) {
  h1 {
    font-size: 2.5rem;
  }

  h2 {
    font-size: 1.8rem;
  }

  h3 {
    font-size: 1.3rem;
  }

  nav .nav-links {
    gap: 1.5rem;
  }

  nav .nav-links a {
    font-size: 0.85rem;
  }

  .hero {
    min-height: 80vh;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .hero .subtitle {
    font-size: 1.1rem;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

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

  .grid-2 {
    grid-template-columns: 1fr;
  }

  .grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  }

  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  section {
    padding: 3rem 0;
  }

  .container {
    padding: 0 1rem;
  }
}

@media (max-width: 480px) {
  h1 {
    font-size: 1.8rem;
  }

  h2 {
    font-size: 1.4rem;
  }

  h3 {
    font-size: 1.1rem;
  }

  nav .nav-links {
    gap: 1rem;
  }

  nav .nav-links a {
    font-size: 0.75rem;
  }

  .hero h1 {
    font-size: 1.8rem;
  }

  .hero .subtitle {
    font-size: 0.95rem;
  }

  .btn {
    padding: 0.7rem 1.2rem;
    font-size: 0.85rem;
  }

  .grid-4 {
    grid-template-columns: 1fr;
  }
}

/* ============================================================================
   14. 工具類
   ============================================================================ */

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.text-left {
  text-align: left;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-5 { margin-bottom: 3rem; }

.pt-1 { padding-top: 0.5rem; }
.pt-2 { padding-top: 1rem; }
.pt-3 { padding-top: 1.5rem; }
.pt-4 { padding-top: 2rem; }
.pt-5 { padding-top: 3rem; }

.pb-1 { padding-bottom: 0.5rem; }
.pb-2 { padding-bottom: 1rem; }
.pb-3 { padding-bottom: 1.5rem; }
.pb-4 { padding-bottom: 2rem; }
.pb-5 { padding-bottom: 3rem; }

.opacity-50 { opacity: 0.5; }
.opacity-75 { opacity: 0.75; }

.hidden {
  display: none !important;
}

.visible {
  display: block !important;
}