/* 요알남 플랫폼 - 다크모드 전용 디자인 시스템 */
/* 블랙, 다크그레이, 오렌지 테마 */

/* ============================
   1. CSS Variables - Dark Theme Only
   ============================ */
:root {
  /* Core Colors - Black & Dark Grey */
  --color-black: #000000;
  --color-dark-1: #0a0a0a;
  --color-dark-2: #111111;
  --color-dark-3: #1a1a1a;
  --color-dark-4: #222222;
  --color-dark-5: #2a2a2a;
  --color-dark-6: #333333;
  --color-dark-7: #3a3a3a;
  --color-dark-8: #444444;
  
  /* Orange Accent Colors */
  --color-orange-primary: #ff6b35;
  --color-orange-hover: #ff8c42;
  --color-orange-active: #ff5722;
  --color-orange-light: #ffa726;
  --color-orange-dark: #e64a19;
  --color-orange-glow: rgba(255, 107, 53, 0.5);
  --color-orange-subtle: rgba(255, 107, 53, 0.1);
  
  /* Text Colors */
  --color-text-primary: #ffffff;
  --color-text-secondary: #b0b0b0;
  --color-text-tertiary: #808080;
  --color-text-muted: #666666;
  --color-text-disabled: #4a4a4a;
  
  /* Semantic Colors */
  --color-success: #4ade80;
  --color-warning: #fbbf24;
  --color-error: #f87171;
  --color-info: #60a5fa;
  
  /* Applied Theme Variables */
  --background: var(--color-black);
  --background-secondary: var(--color-dark-1);
  --background-tertiary: var(--color-dark-2);
  
  --card: var(--color-dark-3);
  --card-hover: var(--color-dark-4);
  --card-active: var(--color-dark-5);
  
  --border: var(--color-dark-5);
  --border-strong: var(--color-dark-6);
  --border-subtle: var(--color-dark-4);
  
  --primary: var(--color-orange-primary);
  --primary-hover: var(--color-orange-hover);
  --primary-active: var(--color-orange-active);
  
  --text: var(--color-text-primary);
  --text-secondary: var(--color-text-secondary);
  --text-muted: var(--color-text-muted);
  
  /* Shadows & Effects */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px var(--color-orange-glow);
  
  /* Radius */
  --radius-sm: 0.375rem;
  --radius: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 999px;
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================
   2. Global Styles
   ============================ */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  border: 0;
}

html {
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--background);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

/* Selection */
::selection {
  background-color: var(--color-orange-subtle);
  color: var(--color-orange-primary);
}

/* ============================
   3. Typography
   ============================ */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.025em;
  color: var(--text);
}

h1 {
  font-size: 3rem;
  font-weight: 800;
}

h2 {
  font-size: 2.25rem;
}

h3 {
  font-size: 1.875rem;
}

h4 {
  font-size: 1.5rem;
}

h5 {
  font-size: 1.25rem;
}

h6 {
  font-size: 1.125rem;
}

p {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--text-secondary);
}

.text-accent {
  color: var(--primary);
}

.text-gradient {
  background: linear-gradient(135deg, var(--primary) 0%, var(--color-orange-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================
   4. Buttons
   ============================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition-base);
  border: none;
  outline: none;
  position: relative;
  overflow: hidden;
}

.btn:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Primary Button - Orange */
.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--color-orange-hover) 100%);
  color: var(--color-black);
  box-shadow: var(--shadow-md), inset 0 1px 0 0 rgba(255, 255, 255, 0.1);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
}

/* Secondary Button - Dark */
.btn-secondary {
  background: var(--color-dark-4);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--color-dark-5);
  border-color: var(--primary);
  color: var(--primary);
}

/* Outline Button */
.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}

.btn-outline:hover:not(:disabled) {
  background: var(--color-orange-subtle);
  box-shadow: var(--shadow-glow);
}

/* Ghost Button */
.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}

.btn-ghost:hover:not(:disabled) {
  background: var(--color-dark-4);
  color: var(--text);
}

/* Icon Button */
.btn-icon {
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border-radius: var(--radius-full);
}

/* Button Sizes */
.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  height: 2rem;
}

.btn-lg {
  padding: 1rem 2rem;
  font-size: 1.125rem;
  height: 3rem;
}

/* ============================
   5. Cards
   ============================ */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary);
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--primary), transparent);
  transform: translateX(-100%);
  transition: transform 0.5s;
}

.card:hover::before {
  transform: translateX(100%);
}

.card-header {
  margin-bottom: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
}

.card-description {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
}

/* ============================
   6. Forms
   ============================ */
.input,
.textarea,
.select {
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--color-dark-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 0.9375rem;
  transition: all var(--transition-base);
}

.input:focus,
.textarea:focus,
.select:focus {
  outline: none;
  border-color: var(--primary);
  background: var(--color-dark-3);
  box-shadow: 0 0 0 3px var(--color-orange-subtle);
}

.input::placeholder,
.textarea::placeholder {
  color: var(--text-muted);
}

.label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

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

/* ============================
   7. Navigation
   ============================ */
.nav {
  background: var(--background-secondary);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(10px);
  background: rgba(0, 0, 0, 0.9);
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-menu {
  display: flex;
  gap: 0.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  padding: 0.5rem 1rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius);
  transition: all var(--transition-base);
  font-weight: 500;
}

.nav-link:hover {
  color: var(--primary);
  background: var(--color-orange-subtle);
}

.nav-link.active {
  color: var(--primary);
  background: var(--color-orange-subtle);
}

/* ============================
   8. Hero Section
   ============================ */
.hero {
  padding: 6rem 0;
  background: linear-gradient(135deg, var(--background) 0%, var(--background-tertiary) 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 30% 50%, var(--color-orange-subtle) 0%, transparent 50%);
  opacity: 0.3;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: 1.5rem;
  background: linear-gradient(135deg, var(--text) 0%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 3rem;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================
   9. Features Grid
   ============================ */
.features {
  padding: 4rem 0;
  background: var(--background-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.feature-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: all var(--transition-base);
  cursor: pointer;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary);
  box-shadow: var(--shadow-xl), var(--shadow-glow);
}

.feature-icon {
  width: 3rem;
  height: 3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-orange-subtle);
  color: var(--primary);
  border-radius: var(--radius-md);
  margin-bottom: 1rem;
  font-size: 1.5rem;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.feature-description {
  color: var(--text-secondary);
  line-height: 1.75;
}

/* ============================
   10. Footer
   ============================ */
.footer {
  background: var(--color-black);
  border-top: 1px solid var(--border);
  padding: 3rem 0;
  margin-top: auto;
}

.footer-content {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 1.5rem;
  text-align: center;
}

.footer-links {
  display: flex;
  gap: 2rem;
  justify-content: center;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.footer-link {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-base);
}

.footer-link:hover {
  color: var(--primary);
}

.footer-text {
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* ============================
   11. Utilities
   ============================ */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 4rem 0;
}

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

.flex {
  display: flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }
.gap-4 { gap: 2rem; }

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

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

.p-1 { padding: 0.5rem; }
.p-2 { padding: 1rem; }
.p-3 { padding: 1.5rem; }
.p-4 { padding: 2rem; }

/* ============================
   12. Animations
   ============================ */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.7;
  }
}

@keyframes glow {
  0%, 100% {
    box-shadow: 0 0 5px var(--color-orange-glow);
  }
  50% {
    box-shadow: 0 0 20px var(--color-orange-glow), 0 0 30px var(--color-orange-glow);
  }
}

.animate-fadeIn {
  animation: fadeIn 0.5s ease-out;
}

.animate-slideUp {
  animation: slideUp 0.5s ease-out;
}

.animate-pulse {
  animation: pulse 2s infinite;
}

.animate-glow {
  animation: glow 2s infinite;
}

/* ============================
   13. Loading States
   ============================ */
.skeleton {
  background: linear-gradient(90deg, var(--color-dark-3) 25%, var(--color-dark-4) 50%, var(--color-dark-3) 75%);
  background-size: 200% 100%;
  animation: loading 1.5s infinite;
  border-radius: var(--radius);
}

@keyframes loading {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

.spinner {
  width: 2rem;
  height: 2rem;
  border: 3px solid var(--color-dark-4);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* ============================
   14. Scrollbar
   ============================ */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--color-dark-2);
}

::-webkit-scrollbar-thumb {
  background: var(--color-dark-6);
  border-radius: var(--radius);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--primary);
}

/* ============================
   15. Responsive
   ============================ */
@media (max-width: 768px) {
  h1 {
    font-size: 2.5rem;
  }
  
  h2 {
    font-size: 2rem;
  }
  
  h3 {
    font-size: 1.5rem;
  }
  
  .hero-title {
    font-size: 2.5rem;
  }
  
  .hero-subtitle {
    font-size: 1.125rem;
  }
  
  .nav-menu {
    display: none;
  }
  
  .nav-menu.active {
    display: flex;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--background-secondary);
    border-bottom: 1px solid var(--border);
    padding: 1rem;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================
   16. Special Effects
   ============================ */
.glow-text {
  text-shadow: 0 0 10px var(--color-orange-glow);
}

.border-glow {
  box-shadow: inset 0 0 0 1px var(--primary), 0 0 10px var(--color-orange-glow);
}

.bg-gradient {
  background: linear-gradient(135deg, var(--background) 0%, var(--background-tertiary) 100%);
}

.bg-pattern {
  background-image: radial-gradient(circle at 1px 1px, var(--color-dark-4) 1px, transparent 1px);
  background-size: 40px 40px;
}