:root {
  --bg-dark: #0a0b0f;
  --surface-dark: #11131a;
  --text-dark: #e9eaf0;
  --muted-dark: #a0a3ad;
  --primary: #6aa1ff;
  --primary-dark: #4b86f5;
  --accent-purple: #8b5cf6;
  --accent-pink: #ec4899;
  --gradient-1: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gradient-2: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --gradient-3: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  --gradient-mesh: radial-gradient(at 20% 30%, rgba(102, 126, 234, 0.3) 0px, transparent 50%),
                   radial-gradient(at 80% 10%, rgba(139, 92, 246, 0.25) 0px, transparent 50%),
                   radial-gradient(at 60% 80%, rgba(236, 72, 153, 0.2) 0px, transparent 50%);
}

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

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

html {
  box-sizing: border-box;
  scroll-behavior: smooth;
  overflow-x: hidden;
}

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

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: var(--gradient-mesh);
  pointer-events: none;
  z-index: 0;
}

/* Marquee */
.marquee-container {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 999;
  background: rgba(102, 126, 234, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
  overflow: hidden;
  height: 50px;
  display: flex;
  align-items: center;
}

/* Header */
.download-header {
  position: fixed;
  top: 50px;
  left: 0;
  right: 0;
  z-index: 998;
  background: rgba(10, 11, 15, 0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  transition: all 0.3s ease;
}

.download-header.scrolled {
  background: rgba(10, 11, 15, 0.95);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.header-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.brand-logo {
  font-size: 2rem;
  filter: drop-shadow(0 0 10px rgba(106, 161, 255, 0.5));
}

.brand-info h1 {
  font-size: 1.25rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.brand-info p {
  font-size: 0.75rem;
  color: var(--muted-dark);
  margin-top: 2px;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.2rem;
  border-radius: 12px;
  font-weight: 500;
  text-decoration: none;
  transition: all 0.3s ease;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-dark);
  cursor: pointer;
}

.nav-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(106, 161, 255, 0.3);
  transform: translateY(-2px);
}

.nav-btn.primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border: none;
  color: white;
}

.nav-btn.primary:hover {
  box-shadow: 0 8px 20px rgba(106, 161, 255, 0.4);
}

/* Main Container */
.download-main {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  padding: 150px 2rem 4rem;
  width: 100%;
  max-width: 100vw;
  overflow-x: hidden;
}

.download-container {
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
  padding: 0;
}

/* Tabs Navigation */
.tabs-nav {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
  background: rgba(255, 255, 255, 0.03);
  padding: 0.5rem;
  border-radius: 16px;
  border: 1px solid rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(10px);
}

.tab-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 1rem;
  border: none;
  background: transparent;
  color: var(--muted-dark);
  border-radius: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.tab-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(106, 161, 255, 0.2), rgba(139, 92, 246, 0.2));
  opacity: 0;
  transition: opacity 0.3s ease;
}

.tab-btn:hover::before {
  opacity: 0.5;
}

.tab-btn.active {
  background: linear-gradient(135deg, var(--primary), var(--accent-purple));
  color: white;
  box-shadow: 0 8px 20px rgba(106, 161, 255, 0.3);
}

.tab-btn.active::before {
  opacity: 0;
}

/* Card Styles */
.download-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 24px;
  padding: 2.5rem;
  backdrop-filter: blur(20px);
  position: relative;
  overflow: hidden;
  transition: all 0.4s ease;
}

.download-card::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: 24px;
  padding: 1px;
  background: linear-gradient(135deg, rgba(106, 161, 255, 0.3), rgba(139, 92, 246, 0.3), rgba(236, 72, 153, 0.3));
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  mask-composite: exclude;
  opacity: 0;
  transition: opacity 0.4s ease;
}

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

.download-card::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(106, 161, 255, 0.1) 0%, transparent 70%);
  opacity: 0;
  transition: opacity 0.4s ease;
  pointer-events: none;
  z-index: 0;
}

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

.card-hidden {
  display: none;
}

/* Form Elements */
.form-section {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  position: relative;
  z-index: 2;
}

.form-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.input-group {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.input-row {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 1rem;
  align-items: end;
}

.input-wrapper {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.sera-input {
  width: 100%;
  padding: 1rem 1.25rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 14px;
  color: var(--text-dark);
  font-size: 1rem;
  transition: all 0.3s ease;
  outline: none;
}

.sera-input:focus {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(106, 161, 255, 0.1), 
              0 8px 20px rgba(106, 161, 255, 0.15);
  transform: translateY(-1px);
}

.sera-input::placeholder {
  color: var(--muted-dark);
}

/* Mode Toggle */
.mode-toggle {
  display: flex;
  gap: 0.75rem;
  padding: 0.5rem;
  background: rgba(255, 255, 255, 0.03);
  border-radius: 12px;
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.mode-option {
  flex: 1;
  position: relative;
}

.mode-option input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.mode-option label {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: 10px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  color: var(--muted-dark);
  background: transparent;
}

.mode-option input:checked + label {
  background: linear-gradient(135deg, var(--primary), var(--accent-purple));
  color: white;
  box-shadow: 0 4px 12px rgba(106, 161, 255, 0.3);
}

/* Select */
.sera-select {
  padding: 1rem 1.25rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 14px;
  color: var(--text-dark);
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  outline: none;
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%236aa1ff' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 3rem;
  position: relative;
  z-index: 1;
}

.sera-select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(106, 161, 255, 0.1);
  z-index: 2;
}

.sera-select option {
  background: var(--surface-dark);
  color: var(--text-dark);
  padding: 0.5rem;
}

/* Buttons */
.sera-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 1rem 2rem;
  border: none;
  border-radius: 14px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.sera-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.2), transparent);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.sera-btn:hover::before {
  opacity: 1;
}

.sera-btn.primary {
  background: linear-gradient(135deg, var(--primary), var(--accent-purple));
  color: white;
}

.sera-btn.primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 30px rgba(106, 161, 255, 0.4);
}

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

.sera-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* Status & Error */
.status-box {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem;
  background: rgba(106, 161, 255, 0.1);
  border: 1px solid rgba(106, 161, 255, 0.3);
  border-radius: 14px;
  margin-top: 1.5rem;
  animation: slideIn 0.3s ease;
}

.status-box.hidden {
  display: none;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.spinner {
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.2);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.error-box {
  padding: 1.25rem;
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  border-radius: 14px;
  color: #fca5a5;
  margin-top: 1.5rem;
  animation: shake 0.4s ease;
}

.error-box.hidden {
  display: none;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}

/* Help Text */
.help-text {
  font-size: 0.875rem;
  color: var(--muted-dark);
  margin-top: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Snackbar */
.snackbar {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(17, 19, 26, 0.95);
  backdrop-filter: blur(20px);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: 12px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5);
  z-index: 9999;
  animation: snackSlide 0.3s ease;
}

.snackbar.hidden {
  display: none;
}

@keyframes snackSlide {
  from {
    opacity: 0;
    transform: translateX(-50%) translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }
}

/* Responsive */

/* Tablet Large (1024px and below) */
@media (max-width: 1024px) {
  .download-container {
    max-width: 100%;
  }

  .input-row {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .download-card {
    padding: 2rem;
  }

  .tabs-nav {
    gap: 0.75rem;
  }

  .tab-btn {
    font-size: 0.95rem;
  }
}

/* Tablet & Mobile (768px and below) */
@media (max-width: 768px) {
  .marquee-container {
    height: 40px;
  }

  .marquee-svg {
    font-size: 1.2rem;
    letter-spacing: 2px;
  }

  .download-header {
    top: 40px;
  }

  .download-main {
    padding: 110px 1rem 3rem;
  }

  .download-container {
    max-width: 100%;
    width: 100%;
  }

  .header-container {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
  }

  .brand {
    flex-direction: row;
    align-items: center;
    text-align: left;
    gap: 0.5rem;
    flex: 1;
  }

  .brand-logo {
    font-size: 1.5rem;
  }

  .brand-info h1 {
    font-size: 1rem;
  }

  .brand-info p {
    font-size: 0.7rem;
  }

  .header-nav {
    display: flex;
    gap: 0.5rem;
  }

  .nav-btn {
    padding: 0.5rem 0.75rem;
    font-size: 0.9rem;
  }

  .nav-btn span:last-child {
    display: none;
  }

  .tabs-nav {
    flex-direction: row;
    gap: 0.5rem;
    padding: 0.4rem;
  }

  .tab-btn {
    padding: 0.65rem 0.5rem;
    font-size: 0.75rem;
    flex-direction: column;
    gap: 0.25rem;
    flex: 1;
  }

  .tab-btn .material-symbols-rounded {
    font-size: 1.25rem;
  }

  .tab-btn span:last-child {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 100%;
  }

  .download-card {
    padding: 1.25rem;
    border-radius: 20px;
  }

  .form-section {
    gap: 1rem;
  }

  .form-label {
    font-size: 0.8rem;
  }

  .input-wrapper {
    width: 100%;
  }

  .sera-input,
  .sera-select {
    padding: 0.875rem 1rem;
    font-size: 0.95rem;
    width: 100%;
    box-sizing: border-box;
  }

  .sera-select {
    background-position: right 0.75rem center;
  }

  .mode-toggle {
    flex-direction: row;
    gap: 0.5rem;
    padding: 0.4rem;
    width: 100%;
  }

  .mode-option {
    flex: 1;
  }

  .mode-option label {
    padding: 0.65rem 0.5rem;
    font-size: 0.85rem;
    width: 100%;
  }

  .sera-btn {
    width: 100%;
    padding: 0.875rem 1.5rem;
    font-size: 0.95rem;
  }

  .help-text {
    font-size: 0.8rem;
  }

  .status-box,
  .error-box {
    padding: 1rem;
    font-size: 0.9rem;
  }
}

/* Mobile Small (480px and below) */
@media (max-width: 480px) {
  .download-main {
    padding: 100px 0.75rem 2rem;
  }

  .header-container {
    padding: 0.5rem 0.75rem;
    flex-direction: column;
  }

  .brand {
    gap: 0.5rem;
    width: 100%;
    justify-content: center;
  }

  .brand-logo {
    font-size: 1.5rem;
  }

  .brand-info h1 {
    font-size: 1rem;
  }

  .brand-info p {
    font-size: 0.65rem;
  }

  .header-nav {
    width: 100%;
    justify-content: center;
  }

  .nav-btn {
    padding: 0.5rem 1rem;
  }

  .tabs-nav {
    flex-direction: row;
    gap: 0.5rem;
    padding: 0.4rem;
  }

  .tab-btn {
    flex-direction: column;
    justify-content: center;
    padding: 0.65rem 0.5rem;
    gap: 0.25rem;
    font-size: 0.7rem;
  }

  .tab-btn .material-symbols-rounded {
    font-size: 1.25rem;
  }

  .tab-btn span:last-child {
    font-size: 0.7rem;
  }

  .download-card {
    padding: 1rem;
    border-radius: 16px;
  }

  .form-section {
    gap: 0.875rem;
  }

  .form-label {
    font-size: 0.75rem;
  }

  .sera-input,
  .sera-select {
    padding: 0.75rem 0.875rem;
    font-size: 0.9rem;
  }

  .mode-toggle {
    flex-direction: row;
    gap: 0.4rem;
  }

  .mode-option label {
    justify-content: center;
    padding: 0.65rem 0.5rem;
    font-size: 0.8rem;
  }

  .sera-btn {
    padding: 0.75rem 1.25rem;
    font-size: 0.9rem;
  }

  .snackbar {
    left: 1rem;
    right: 1rem;
    transform: none;
    bottom: 1rem;
    font-size: 0.85rem;
  }

  .help-text {
    font-size: 0.75rem;
  }
}

/* Mobile Extra Small (360px and below) */
@media (max-width: 360px) {
  .download-main {
    padding: 95px 0.5rem 1.5rem;
  }

  .download-card {
    padding: 0.875rem;
  }

  .tab-btn {
    font-size: 0.65rem;
    padding: 0.5rem 0.25rem;
  }

  .tab-btn .material-symbols-rounded {
    font-size: 1.1rem;
  }

  .sera-input,
  .sera-select {
    padding: 0.65rem 0.75rem;
    font-size: 0.85rem;
  }

  .sera-btn {
    padding: 0.65rem 1rem;
    font-size: 0.85rem;
  }

  .form-label {
    font-size: 0.7rem;
  }

  .help-text {
    font-size: 0.7rem;
  }

  .mode-option label {
    padding: 0.5rem 0.25rem;
    font-size: 0.75rem;
  }
}

/* Landscape Mobile */
@media (max-height: 500px) and (orientation: landscape) {
  .download-main {
    padding-top: 90px;
  }

  .download-card {
    padding: 1rem;
  }

  .form-section {
    gap: 0.75rem;
  }

  .tabs-nav {
    flex-direction: row;
  }

  .tab-btn {
    padding: 0.5rem 0.75rem;
    font-size: 0.8rem;
  }
}

/* Animations */
@keyframes glow {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 1; }
}

.glow-effect {
  animation: glow 2s ease-in-out infinite;
}

/* Floating Animation */
@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-10px); }
}

.float-animation {
  animation: float 3s ease-in-out infinite;
}