/* ==========================================================================
   Twitter Video Downloader - Official Brand Styling
   Authentic X (Twitter) Black & White Design System
   Minimal, Modern, High-Contrast, and Clean
   ========================================================================== */

:root {
  /* Authentic X Brand Colors */
  --x-black: #000000;
  --x-black-surface: #16181C;
  --x-black-card: #1E2024;
  --x-black-hover: #272A30;
  
  --x-border-dark: #2F3336;
  --x-border-subtle: #202327;
  
  --x-gray-text: #71767B;
  --x-gray-light: #A0A5AB;
  --x-gray-subtle: #E7E9EA;
  
  --x-white: #FFFFFF;
  --x-blue-accent: #1D9BF0;

  /* Pure White Content Section Neutrals */
  --content-bg: #FFFFFF;
  --content-text-main: #0F1419;
  --content-text-muted: #536471;
  --content-border: #CFD9DE;
  --content-border-light: #EFF3F4;
  --content-surface: #F7F9F9;

  /* Feedback Colors */
  --color-error-bg: #2C1517;
  --color-error-border: #F4212E;
  --color-error-text: #FF7B82;

  --font-main: 'Plus Jakarta Sans', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-pill: 9999px;

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-main);
  background-color: var(--x-black);
  color: var(--x-white);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ==========================================================================
   1. Minimal Header: ONLY the Official X Logo
   ========================================================================== */
.header {
  background-color: var(--x-black);
  width: 100%;
  padding: 24px 20px 16px 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  border-bottom: 1px solid var(--x-border-dark);
}

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

.logo-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
  text-decoration: none;
}

.logo-link:hover {
  opacity: 0.85;
  transform: scale(1.04);
}

.x-header-logo {
  width: 32px;
  height: 32px;
  display: block;
}

/* ==========================================================================
   2. Hero Section: Pure Black (#000000) with White Typography
   ========================================================================== */
.hero-section {
  background-color: var(--x-black);
  color: var(--x-white);
  padding: 56px 20px 64px 20px;
  display: flex;
  justify-content: center;
  position: relative;
}

.hero-container {
  width: 100%;
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.hero-title {
  font-size: 2.75rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--x-white);
  margin-bottom: 12px;
  line-height: 1.15;
}

.hero-subtitle {
  font-size: 1.125rem;
  font-weight: 400;
  color: var(--x-gray-light);
  margin-bottom: 36px;
  max-width: 540px;
  line-height: 1.45;
}

/* ==========================================================================
   Downloader Form: Input & Download Button
   ========================================================================== */
.downloader-form {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

@media (min-width: 640px) {
  .downloader-form {
    flex-direction: row;
    align-items: stretch;
  }
}

.input-wrapper {
  position: relative;
  flex: 1;
  display: flex;
  align-items: center;
}

.paste-btn {
  position: absolute;
  left: 14px;
  background: transparent;
  border: none;
  color: var(--x-gray-text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
  z-index: 2;
}

.paste-btn:hover {
  color: var(--x-white);
  background-color: rgba(255, 255, 255, 0.08);
}

.clear-btn {
  position: absolute;
  right: 14px;
  background: transparent;
  border: none;
  color: var(--x-gray-text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
  z-index: 2;
}

.clear-btn:hover {
  color: var(--x-white);
  background-color: rgba(255, 255, 255, 0.08);
}

.clear-btn.hidden {
  display: none !important;
}

.url-input {
  width: 100%;
  height: 54px;
  background-color: var(--x-black-surface);
  border: 1.5px solid var(--x-border-dark);
  border-radius: var(--radius-pill);
  padding: 0 46px 0 48px;
  font-size: 1rem;
  font-family: var(--font-main);
  color: var(--x-white);
  outline: none;
  transition: border-color var(--transition-fast), background-color var(--transition-fast), box-shadow var(--transition-fast);
}

.url-input::placeholder {
  color: var(--x-gray-text);
  font-weight: 400;
}

.url-input:hover {
  border-color: #536471;
}

.url-input:focus {
  border-color: var(--x-white);
  background-color: #0f1115;
  box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.15);
}

/* Prominent Download Button (High-Contrast Pure White on Black) */
.download-btn {
  height: 54px;
  padding: 0 36px;
  background-color: var(--x-white);
  color: var(--x-black);
  border: none;
  border-radius: var(--radius-pill);
  font-size: 1.05rem;
  font-weight: 700;
  font-family: var(--font-main);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  white-space: nowrap;
  transition: background-color var(--transition-fast), transform var(--transition-fast), opacity var(--transition-fast);
}

.download-btn:hover {
  background-color: #E6E6E6;
  transform: translateY(-1px);
}

.download-btn:active {
  transform: translateY(0);
  background-color: #D4D4D4;
}

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

/* Spinner */
.spinner {
  width: 22px;
  height: 22px;
  animation: spin 0.8s linear infinite;
}

.spinner-track {
  opacity: 0.2;
}

.spinner-head {
  stroke: currentColor;
}

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

.hidden {
  display: none !important;
}

/* ==========================================================================
   Feedback: Loading Status & Error Alert
   ========================================================================== */
.status-container {
  width: 100%;
  margin-top: 24px;
}

.status-loading {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 12px 24px;
  background-color: var(--x-black-surface);
  border: 1px solid var(--x-border-dark);
  border-radius: var(--radius-pill);
  font-size: 0.95rem;
  color: var(--x-gray-subtle);
}

.pulse-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--x-white);
  animation: pulse 1.2s infinite ease-in-out;
}

@keyframes pulse {
  0% { transform: scale(0.8); opacity: 0.4; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.8); opacity: 0.4; }
}

.error-container {
  width: 100%;
  margin-top: 24px;
  background-color: var(--color-error-bg);
  border: 1px solid var(--color-error-border);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  text-align: left;
}

.error-icon {
  color: var(--color-error-border);
  flex-shrink: 0;
  margin-top: 2px;
}

.error-content strong {
  display: block;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--x-white);
  margin-bottom: 4px;
}

.error-content p {
  font-size: 0.875rem;
  color: var(--color-error-text);
  line-height: 1.4;
}

.error-action-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--x-white);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ==========================================================================
   Result Card: Real Video Preview & Download Options
   ========================================================================== */
.result-container {
  width: 100%;
  margin-top: 36px;
  text-align: left;
}

.result-card {
  background-color: var(--x-black-surface);
  border: 1px solid var(--x-border-dark);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

@media (min-width: 720px) {
  .result-card {
    flex-direction: row;
  }
}

.result-video-wrapper {
  background-color: #000000;
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 1 1 45%;
  min-height: 280px;
  max-height: 480px;
  border-bottom: 1px solid var(--x-border-dark);
}

@media (min-width: 720px) {
  .result-video-wrapper {
    border-bottom: none;
    border-right: 1px solid var(--x-border-dark);
  }
}

.video-preview {
  width: 100%;
  height: 100%;
  max-height: 480px;
  object-fit: contain;
  display: block;
}

.result-details {
  flex: 1 1 55%;
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.result-meta-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.author-info {
  display: flex;
  align-items: center;
  gap: 10px;
}

.author-avatar {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--x-border-dark);
}

.author-text {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}

.author-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--x-white);
}

.author-handle {
  font-size: 0.8rem;
  color: var(--x-gray-text);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
  font-weight: 700;
}

.quality-badge {
  background-color: var(--x-border-subtle);
  border: 1px solid var(--x-border-dark);
  color: var(--x-white);
}

.video-title {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--x-gray-subtle);
  line-height: 1.45;
  margin-bottom: 20px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* Quality Selector */
.quality-selector-wrapper {
  margin-bottom: 20px;
}

.quality-select-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--x-gray-text);
  margin-bottom: 8px;
}

.quality-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.quality-btn {
  background-color: var(--x-black-card);
  border: 1px solid var(--x-border-dark);
  color: var(--x-gray-subtle);
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  font-size: 0.825rem;
  font-weight: 600;
  font-family: var(--font-main);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.quality-btn:hover {
  background-color: var(--x-black-hover);
  border-color: #536471;
  color: var(--x-white);
}

.quality-btn.active {
  background-color: var(--x-white);
  border-color: var(--x-white);
  color: var(--x-black);
  font-weight: 700;
}

.meta-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  padding: 14px 0;
  border-top: 1px solid var(--x-border-dark);
  border-bottom: 1px solid var(--x-border-dark);
  margin-bottom: 22px;
}

.meta-item {
  display: flex;
  flex-direction: column;
}

.meta-label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--x-gray-text);
  margin-bottom: 2px;
}

.meta-val {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--x-white);
}

.highlight-val {
  color: #00BA7C;
}

/* Action Buttons */
.result-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.action-btn {
  width: 100%;
  height: 46px;
  border-radius: var(--radius-pill);
  font-size: 0.95rem;
  font-weight: 700;
  font-family: var(--font-main);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.download-action-btn {
  background-color: var(--x-white);
  color: var(--x-black);
  border: none;
}

.download-action-btn:hover {
  background-color: #E6E6E6;
  transform: translateY(-1px);
}

.x-watch-action-btn {
  background-color: transparent;
  color: var(--x-white);
  border: 1px solid var(--x-border-dark);
}

.x-watch-action-btn:hover {
  background-color: rgba(255, 255, 255, 0.08);
  border-color: #536471;
}

.secondary-action-btn {
  background-color: transparent;
  color: var(--x-gray-subtle);
  border: 1px solid var(--x-border-dark);
}

.secondary-action-btn:hover {
  background-color: rgba(255, 255, 255, 0.05);
  color: var(--x-white);
}

.text-action-btn {
  background: transparent;
  border: none;
  color: var(--x-gray-text);
  font-weight: 600;
  font-size: 0.875rem;
  height: 36px;
}

.text-action-btn:hover {
  color: var(--x-white);
  text-decoration: underline;
}

/* ==========================================================================
   3. Content Section: Pure White (#FFFFFF) Immediately Below Hero
   ========================================================================== */
.content-section {
  background-color: var(--content-bg);
  color: var(--content-text-main);
  padding: 80px 20px 88px 20px;
  flex: 1;
}

.content-container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--content-text-main);
  text-align: center;
  margin-bottom: 52px;
}

/* 3-Step Guide Grid */
.steps-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}

@media (min-width: 768px) {
  .steps-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
  }
}

.step-card {
  background-color: var(--content-bg);
  border: 1px solid var(--content-border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  transition: border-color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
}

.step-card:hover {
  border-color: #8B98A5;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.05);
}

.step-badge {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--x-black);
  color: var(--x-white);
  font-size: 1.25rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
}

.step-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--content-text-main);
  margin-bottom: 12px;
}

.step-desc {
  font-size: 0.95rem;
  color: var(--content-text-muted);
  line-height: 1.55;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
  background-color: var(--content-bg);
  border-top: 1px solid var(--content-border-light);
  padding: 28px 20px;
  text-align: center;
}

.footer-container {
  max-width: 960px;
  margin: 0 auto;
}

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