/* ============================================
   STÉRO Lite - Landing Page Styles
   모바일 퍼스트 디자인
   ============================================ */

:root {
  --gradient-start: #ff6b35;
  --gradient-end: #7b2cbf;
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.9);
  --text-muted: rgba(255, 255, 255, 0.7);
  --card-bg: rgba(255, 255, 255, 0.1);
  --card-border: rgba(255, 255, 255, 0.2);
  --button-bg: rgba(255, 255, 255, 0.2);
  --button-hover: rgba(255, 255, 255, 0.3);
  --max-width: 1200px;
  --border-radius: 24px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 3rem;
  --spacing-xl: 4rem;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', system-ui, sans-serif;
  background: linear-gradient(135deg, var(--gradient-start) 0%, var(--gradient-end) 100%);
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ============================================
   공통 스타일
   ============================================ */

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-sm);
}

section {
  padding: var(--spacing-xl) var(--spacing-sm);
}

h1 {
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(2rem, 6vw, 3rem);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  text-align: center;
  letter-spacing: -0.01em;
}

h3 {
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

p {
  font-size: clamp(1rem, 3vw, 1.125rem);
  line-height: 1.7;
  color: var(--text-secondary);
}

a {
  color: var(--text-primary);
  text-decoration: none;
  transition: opacity 0.3s ease;
}

a:hover {
  opacity: 0.8;
}

/* ============================================
   Hero Section
   ============================================ */

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: var(--spacing-xl) var(--spacing-sm);
  position: relative;
  overflow: hidden;
}

.hero .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  position: relative;
  z-index: 1;
}

.hero-content {
  max-width: 800px;
  margin-bottom: var(--spacing-lg);
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.hero h1 {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
  background: linear-gradient(180deg, #ffffff 0%, rgba(255, 255, 255, 0.8) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero h1 .app-icon {
  width: clamp(48px, 9.6vw, 80px);
  height: clamp(48px, 9.6vw, 80px);
  border-radius: 22%;
  object-fit: cover;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  flex-shrink: 0;
  -webkit-background-clip: unset;
  -webkit-text-fill-color: unset;
  background-clip: unset;
}

.hero .slogan {
  font-size: clamp(1.25rem, 4vw, 1.75rem);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  font-weight: 300;
}

.app-store-badge {
  display: inline-block;
  margin-top: var(--spacing-md);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--button-bg);
  backdrop-filter: blur(10px);
  border-radius: var(--border-radius);
  border: 1px solid var(--card-border);
  font-size: clamp(1rem, 3vw, 1.125rem);
  font-weight: 500;
  transition: all 0.3s ease;
}

.app-store-badge:hover {
  background: var(--button-hover);
  transform: translateY(-2px);
}

.iphone-mockup-wrapper {
  position: relative;
  width: 100%;
  max-width: 300px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
}

.iphone-background {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
  opacity: 0.8;
  pointer-events: none;
  mask-image: linear-gradient(
    to right,
    transparent 0%,
    black 10%,
    black 90%,
    transparent 100%
  );
  -webkit-mask-image: linear-gradient(
    to right,
    transparent 0%,
    black 10%,
    black 90%,
    transparent 100%
  );
}

.iphone-mockup {
  width: 100%;
  max-width: 300px;
  height: auto;
  margin: 0 auto;
  border-radius: 40px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  background: rgba(0, 0, 0, 0.2);
  position: relative;
  overflow: hidden;
  aspect-ratio: 9/19.5;
  z-index: 1;
}

.iphone-mockup img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  position: relative;
  z-index: 1;
  border-radius: 40px;
}

/* ============================================
   Features Section
   ============================================ */

.features {
  background: rgba(0, 0, 0, 0.1);
  backdrop-filter: blur(10px);
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

@media (min-width: 768px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.feature-card {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius);
  padding: var(--spacing-md);
  transition: all 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-5px);
  background: rgba(255, 255, 255, 0.15);
}

.feature-icon {
  width: 2.5rem;
  height: 2.5rem;
  margin-bottom: var(--spacing-sm);
  display: block;
  object-fit: contain;
}

.feature-card h3 {
  font-size: clamp(1.25rem, 3vw, 1.5rem);
  margin-bottom: var(--spacing-xs);
}

.feature-card p {
  font-size: clamp(0.9rem, 2.5vw, 1rem);
  color: var(--text-muted);
}

/* ============================================
   Screenshots Section
   ============================================ */

.screenshots {
  padding: var(--spacing-xl) var(--spacing-sm);
  overflow: hidden;
}

.screenshots-wrapper {
  margin-top: var(--spacing-lg);
  position: relative;
  width: 100%;
  overflow: hidden;
  mask-image: linear-gradient(
    to right,
    transparent,
    black 10%,
    black 90%,
    transparent
  );
  -webkit-mask-image: linear-gradient(
    to right,
    transparent,
    black 10%,
    black 90%,
    transparent
  );
}

.screenshots-carousel {
  display: flex;
  gap: var(--spacing-md);
  animation: scroll 40s linear infinite;
  will-change: transform;
}

.screenshots-carousel:hover {
  animation-play-state: paused;
}

.screenshot-item {
  flex: 0 0 auto;
  width: 250px;
  border-radius: 30px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
  overflow: hidden;
  background: transparent;
  aspect-ratio: 9/19.5;
  position: relative;
}

.screenshot-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

@keyframes scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(-250px * 9 - var(--spacing-md) * 9));
  }
}

@media (min-width: 768px) {
  .screenshot-item {
    width: 280px;
  }
  
  @keyframes scroll {
    0% {
      transform: translateX(0);
    }
    100% {
      transform: translateX(calc(-280px * 9 - var(--spacing-md) * 9));
    }
  }
}

@media (min-width: 1024px) {
  .screenshot-item {
    width: 300px;
  }
  
  @keyframes scroll {
    0% {
      transform: translateX(0);
    }
    100% {
      transform: translateX(calc(-300px * 9 - var(--spacing-md) * 9));
    }
  }
}

/* ============================================
   Footer
   ============================================ */

.footer {
  background: rgba(0, 0, 0, 0.2);
  backdrop-filter: blur(10px);
  padding: var(--spacing-lg) var(--spacing-sm);
  text-align: center;
  border-top: 1px solid var(--card-border);
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  align-items: center;
}

.footer-links {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
  justify-content: center;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: clamp(0.9rem, 2.5vw, 1rem);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 12px;
  transition: all 0.3s ease;
}

.footer-links a:hover {
  background: rgba(255, 255, 255, 0.1);
  opacity: 1;
}

.footer-copyright {
  color: var(--text-muted);
  font-size: clamp(0.875rem, 2vw, 1rem);
  margin-top: var(--spacing-sm);
}

/* ============================================
   Privacy Page
   ============================================ */

.privacy-page {
  min-height: 100vh;
  padding: var(--spacing-xl) var(--spacing-sm);
}

.privacy-container {
  max-width: 800px;
  margin: 0 auto;
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
}

.privacy-page h1 {
  font-size: clamp(2rem, 6vw, 2.5rem);
  margin-bottom: var(--spacing-lg);
  text-align: center;
}

.privacy-page h2 {
  font-size: clamp(1.5rem, 4vw, 1.75rem);
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  text-align: left;
}

.privacy-page p {
  margin-bottom: var(--spacing-md);
  line-height: 1.8;
}

.privacy-page ul {
  margin-left: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.privacy-page li {
  margin-bottom: var(--spacing-xs);
  line-height: 1.8;
  color: var(--text-secondary);
}

.privacy-page .contact-info {
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--card-border);
}

.privacy-page .back-link {
  display: inline-block;
  margin-top: var(--spacing-lg);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--button-bg);
  backdrop-filter: blur(10px);
  border-radius: var(--border-radius);
  border: 1px solid var(--card-border);
  transition: all 0.3s ease;
}

.privacy-page .back-link:hover {
  background: var(--button-hover);
  transform: translateY(-2px);
}

/* ============================================
   반응형 개선
   ============================================ */

@media (min-width: 768px) {
  section {
    padding: var(--spacing-xl) var(--spacing-md);
  }
  
  .hero {
    padding: var(--spacing-xl) var(--spacing-md);
  }
  
  .iphone-mockup-wrapper {
    max-width: 350px;
  }
  
  .iphone-mockup {
    max-width: 350px;
  }
  
  .screenshot-item {
    max-width: 300px;
  }
}

@media (min-width: 1024px) {
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .features-grid {
    gap: var(--spacing-lg);
  }
  
  .screenshots-grid {
    gap: var(--spacing-lg);
  }
}

/* ============================================
   접근성 개선
   ============================================ */

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* 포커스 스타일 */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--text-primary);
  outline-offset: 4px;
  border-radius: 4px;
}