/* ==========================================
   DESIGN SYSTEM - Modern Downloader App
   ========================================== */

/* === GOOGLE FONTS === */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

/* === CSS VARIABLES === */
:root {
  /* Colors - Vibrant Gradient Palette */
  --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  --success-gradient: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);

  /* Solid Colors */
  --bg-dark: #0a0e27;
  --bg-darker: #060920;
  --card-bg: rgba(255, 255, 255, 0.05);
  --card-border: rgba(255, 255, 255, 0.1);
  --text-primary: #ffffff;
  --text-secondary: #a0aec0;
  --text-muted: #718096;

  /* Accent Colors */
  --purple: #667eea;
  --pink: #f093fb;
  --blue: #4facfe;
  --cyan: #00f2fe;
  --green: #43e97b;

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px rgba(102, 126, 234, 0.3);

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* === RESET & BASE STYLES === */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Animated Background Gradient */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(circle at 20% 80%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(240, 147, 251, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 40% 40%, rgba(79, 172, 254, 0.1) 0%, transparent 50%);
  z-index: -1;
  animation: backgroundshift 15s ease infinite;
}

@keyframes backgroundshift {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.8;
  }
}

/* === TYPOGRAPHY === */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
}

h2 {
  font-size: clamp(1.5rem, 4vw, 2.5rem);
  font-weight: 700;
}

h3 {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
}

p {
  margin-bottom: var(--spacing-sm);
  color: var(--text-secondary);
}

/* === CONTAINER === */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* === HEADER === */
.header {
  padding: var(--spacing-md) 0;
  position: relative;
  z-index: 100;
}

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

/* === HAMBURGER MENU (Hidden by default) === */
.nav-toggle {
  display: none !important;
  visibility: hidden;
  position: absolute;
  opacity: 0;
}

.nav-toggle-label {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  cursor: pointer;
  z-index: 1001;
  position: relative;
}

.nav-toggle-label span {
  display: block;
  background: var(--text-primary);
  height: 3px;
  width: 28px;
  border-radius: 2px;
  position: relative;
  transition: all var(--transition-base);
}

.nav-toggle-label span::before,
.nav-toggle-label span::after {
  content: '';
  display: block;
  background: var(--text-primary);
  height: 3px;
  width: 28px;
  border-radius: 2px;
  position: absolute;
  transition: all var(--transition-base);
}

.nav-toggle-label span::before {
  top: -9px;
}

.nav-toggle-label span::after {
  top: 9px;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  gap: var(--spacing-lg);
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-fast);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary-gradient);
  transition: width var(--transition-base);
}

.nav-links a:hover {
  color: var(--text-primary);
}

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

/* === HERO SECTION === */
.hero {
  text-align: center;
  padding: var(--spacing-2xl) 0;
  margin-bottom: var(--spacing-xl);
}

.hero h1 {
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-md);
  animation: gradientshift 3s ease infinite;
  background-size: 200% 200%;
}

@keyframes gradientshift {

  0%,
  100% {
    background-position: 0% 50%;
  }

  50% {
    background-position: 100% 50%;
  }
}

.hero p {
  font-size: 1.25rem;
  max-width: 600px;
  margin: 0 auto var(--spacing-lg);
  color: var(--text-secondary);
}

/* === GLASSMORPHISM CARD === */
.glass-card {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-base);
}

.glass-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border-color: rgba(102, 126, 234, 0.3);
}

/* === TAB NAVIGATION === */
.tab-navigation {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  background: rgba(255, 255, 255, 0.03);
  padding: var(--spacing-xs);
  border-radius: var(--radius-md);
  border: 1px solid var(--card-border);
}

.tab-btn {
  flex: 1;
  padding: var(--spacing-md) var(--spacing-lg);
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
  position: relative;
  font-family: 'Inter', sans-serif;
}

.tab-btn.active {
  background: var(--primary-gradient);
  color: var(--text-primary);
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.tab-btn:not(.active):hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
}

/* === TAB CONTENT === */
.tab-content {
  display: none;
  animation: fadein var(--transition-base);
}

.tab-content.active {
  display: block;
}

@keyframes fadein {
  from {
    opacity: 0;
    transform: translateY(10px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* === FORM STYLES === */
.download-form {
  margin-bottom: var(--spacing-xl);
}

.form-group {
  margin-bottom: var(--spacing-md);
}

label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 600;
  color: var(--text-primary);
}

textarea,
input[type="text"] {
  width: 100%;
  padding: var(--spacing-md);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: 'Inter', monospace;
  font-size: 0.95rem;
  resize: vertical;
  transition: all var(--transition-base);
}

textarea {
  min-height: 150px;
}

textarea:focus,
input[type="text"]:focus {
  outline: none;
  border-color: var(--purple);
  background: rgba(255, 255, 255, 0.08);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

textarea::placeholder,
input[type="text"]::placeholder {
  color: var(--text-muted);
}

/* === BUTTONS === */
.btn {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  font-family: 'Inter', sans-serif;
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.btn-primary {
  background: var(--primary-gradient);
  color: var(--text-primary);
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-full {
  width: 100%;
  justify-content: center;
}

/* === PROGRESS BAR === */
.progress-container {
  display: none;
  margin-top: var(--spacing-lg);
}

.progress-container.active {
  display: block;
  animation: fadein var(--transition-base);
}

.progress-bar-wrapper {
  background: rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-full);
  height: 12px;
  overflow: hidden;
  margin-bottom: var(--spacing-sm);
  border: 1px solid var(--card-border);
}

.progress-bar {
  height: 100%;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
  box-shadow: 0 0 10px rgba(79, 172, 254, 0.5);
}

.progress-text {
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
}

/* === DOWNLOAD LINKS === */
.download-links {
  margin-top: var(--spacing-xl);
  display: none;
}

.download-links.active {
  display: block;
  animation: fadein var(--transition-base);
}

.download-links h3 {
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.download-item {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: all var(--transition-base);
}

.download-item:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(102, 126, 234, 0.3);
  transform: translateX(4px);
}

.download-item-info {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.download-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: var(--success-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.download-filename {
  font-weight: 600;
  color: var(--text-primary);
}

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

.download-btn {
  padding: var(--spacing-xs) var(--spacing-md);
  background: var(--primary-gradient);
  color: var(--text-primary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  transition: all var(--transition-base);
}

.download-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

/* === LOADING SPINNER === */
.spinner {
  display: inline-block;
  width: 16px;
  height: 16px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: var(--text-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* === ALERTS === */
.alert {
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  border-left: 4px solid;
  animation: fadein var(--transition-base);
}

.alert-error {
  background: rgba(245, 87, 108, 0.1);
  border-color: #f5576c;
  color: #ff8a9b;
}

.alert-success {
  background: rgba(67, 233, 123, 0.1);
  border-color: var(--green);
  color: #5dffa0;
}

.alert-info {
  background: rgba(79, 172, 254, 0.1);
  border-color: var(--blue);
  color: #6db9ff;
}

/* === FOOTER === */
.footer {
  margin-top: var(--spacing-2xl);
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--card-border);
  text-align: center;
}

.footer p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* === RESPONSIVE DESIGN === */
@media (max-width: 768px) {
  .nav-links {
    gap: var(--spacing-md);
  }

  .hero {
    padding: var(--spacing-xl) 0;
  }

  .glass-card {
    padding: var(--spacing-lg);
  }

  .tab-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.9rem;
  }

  .download-item {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-sm);
  }

  .download-btn {
    width: 100%;
    text-align: center;
  }
}

@media (max-width: 480px) {

  /* Show hamburger button on mobile */
  .nav-toggle-label {
    display: flex;
  }

  /* Mobile Navigation Menu - Hidden by default */
  .nav-links {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(10, 14, 39, 0.98);
    backdrop-filter: blur(10px);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-xl);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    z-index: 999;
  }

  /* Show menu when checkbox is checked */
  .nav-toggle:checked~.nav-links {
    transform: translateX(0);
  }

  /* Animate hamburger to X when active */
  .nav-toggle:checked+.nav-toggle-label span {
    background: transparent;
  }

  .nav-toggle:checked+.nav-toggle-label span::before {
    transform: rotate(45deg);
    top: 0;
  }

  .nav-toggle:checked+.nav-toggle-label span::after {
    transform: rotate(-45deg);
    top: 0;
  }

  .nav-links a {
    font-size: 1.5rem;
    font-weight: 600;
  }

  .tab-navigation {
    flex-direction: column;
  }

  .tab-btn {
    width: 100%;
  }
}

/* Hide hamburger on larger screens */
@media (min-width: 481px) {

  .nav-toggle,
  .nav-toggle-label {
    display: none;
  }
}

/* === UTILITY CLASSES === */
.text-center {
  text-align: center;
}

.text-gradient {
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.mt-1 {
  margin-top: var(--spacing-sm);
}

.mt-2 {
  margin-top: var(--spacing-md);
}

.mt-3 {
  margin-top: var(--spacing-lg);
}

.mb-1 {
  margin-bottom: var(--spacing-sm);
}

.mb-2 {
  margin-bottom: var(--spacing-md);
}

.mb-3 {
  margin-bottom: var(--spacing-lg);
}

/* === ACTIVE NAV LINK === */
.nav-links a.active {
  color: var(--text-primary);
  font-weight: 600;
}

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

/* === SEO CONTENT SECTIONS === */
.seo-content h2 {
  color: var(--text-primary);
}

.seo-content h3 {
  color: var(--text-primary);
  font-size: 1.5rem;
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
}

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

.seo-content ul,
.seo-content ol {
  margin-bottom: var(--spacing-md);
}

/* === STEPS GRID === */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-top: var(--spacing-lg);
}

.step-item {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  text-align: center;
  transition: all var(--transition-base);
}

.step-item:hover {
  background: rgba(255, 255, 255, 0.05);
  transform: translateY(-4px);
  border-color: rgba(102, 126, 234, 0.3);
}

.step-number {
  width: 60px;
  height: 60px;
  margin: 0 auto var(--spacing-md);
  background: var(--primary-gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text-primary);
  box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.step-item h3 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.step-item p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 0;
}

/* === FOOTER LINKS === */
.footer a {
  text-decoration: none;
  transition: color var(--transition-fast);
}

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