/* ==========================================
   TikTok Downloader - Complete Modern Stylesheet
   ========================================== */

/* ------------------------------------------
   1. CSS RESET & NORMALIZE
   ------------------------------------------ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
}

input, button, textarea, select {
  font: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

/* ------------------------------------------
   2. CSS VARIABLES & THEME DEFINITIONS
   ------------------------------------------ */
:root {
  /* TikTok Brand */
  --primary: #FE2C55;
  --primary-dark: #D92348;
  --primary-light: #FF6B81;
  --accent: #25F4EE;
  --accent-dark: #1BC4BE;
  
  /* Dark Mode (default) */
  --bg-primary: #000000;
  --bg-secondary: #121212;
  --bg-card: #1A1A1A;
  --bg-elevated: #242424;
  --text-primary: #FFFFFF;
  --text-secondary: #A0A0A0;
  --text-tertiary: #666666;
  --border: #2A2A2A;
  
  /* Semantic */
  --success: #22C55E;
  --warning: #F59E0B;
  --error: #EF4444;
  --info: #3B82F6;
  
  /* Spacing (base 4px) */
  --space-1: 4px;  --space-2: 8px;   --space-3: 12px;
  --space-4: 16px; --space-6: 24px;  --space-8: 32px;
  --space-12: 48px; --space-16: 64px;
  
  /* Radius */
  --radius-sm: 6px; --radius-md: 8px; --radius-lg: 12px;
  --radius-xl: 16px; --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.15);
  --shadow-glow-red: 0 0 20px rgba(254,44,85,0.4);
  --shadow-glow-cyan: 0 0 20px rgba(37,244,238,0.4);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
  
  /* Z-index */
  --z-base: 1; --z-sticky: 200; --z-modal: 400; --z-toast: 500;
}

/* Light Theme Override Class */
[data-theme="light"] {
  --bg-primary: #FFFFFF;
  --bg-secondary: #F8F8F8;
  --bg-card: #FFFFFF;
  --bg-elevated: #F0F0F0;
  --text-primary: #1A1A1A;
  --text-secondary: #666666;
  --text-tertiary: #999999;
  --border: #E0E0E0;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg-primary: #FFFFFF;
    --bg-secondary: #F8F8F8;
    --bg-card: #FFFFFF;
    --bg-elevated: #F0F0F0;
    --text-primary: #1A1A1A;
    --text-secondary: #666666;
    --text-tertiary: #999999;
    --border: #E0E0E0;
  }
}

/* ------------------------------------------
   3. BASE & TYPOGRAPHY STYLES
   ------------------------------------------ */
body {
  font-family: 'Inter', 'Poppins', system-ui, -apple-system, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: var(--text-primary);
  background: var(--bg-primary);
  transition: background-color var(--transition-base), color var(--transition-base);
  overflow-x: hidden;
  position: relative;
}

h1 { font-size: 36px; font-weight: 700; line-height: 1.2; }
h2 { font-size: 28px; font-weight: 700; line-height: 1.3; }
h3 { font-size: 22px; font-weight: 600; line-height: 1.4; }
p { color: var(--text-secondary); }

/* ------------------------------------------
   4. LAYOUT CONTAINERS
   ------------------------------------------ */
.main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 var(--space-4) var(--space-16);
  display: flex;
  flex-direction: column;
  gap: var(--space-12);
}

/* ------------------------------------------
   5. HEADER & NAVIGATION STYLES
   ------------------------------------------ */
.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-8);
  background: rgba(18, 18, 18, 0.75);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition-base), border-color var(--transition-base);
}

[data-theme="light"] .header {
  background: rgba(255, 255, 255, 0.85);
}

.header__logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.header__logo img {
  border-radius: var(--radius-sm);
}

.header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.header__nav a {
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.header__nav a:hover,
.header__nav a:focus-visible {
  color: var(--primary);
}

.header__theme-toggle {
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-full);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  font-size: 1.1rem;
  transition: transform var(--transition-fast), background var(--transition-fast);
}

.header__theme-toggle:hover {
  transform: scale(1.08);
  background: var(--bg-card);
}

/* ------------------------------------------
   6. HERO SECTION
   ------------------------------------------ */
.hero {
  text-align: center;
  padding-top: var(--space-12);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  position: relative;
}

.hero::before {
  content: "";
  position: absolute;
  top: -20px;
  left: 50%;
  transform: translateX(-50%);
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, var(--primary) 0%, var(--accent) 100%);
  opacity: 0.15;
  filter: blur(100px);
  border-radius: 50%;
  pointer-events: none;
  z-index: -1;
}

.hero__title {
  background: linear-gradient(135deg, var(--text-primary) 30%, var(--primary-light) 70%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  max-width: 800px;
}

.hero__subtitle {
  font-size: 1.2rem;
  max-width: 600px;
  color: var(--text-secondary);
}

/* ------------------------------------------
   7. DOWNLOADER FORM & INPUT STYLES
   ------------------------------------------ */
.downloader {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  width: 100%;
  max-width: 720px;
  margin: 0 auto;
}

.downloader__form {
  display: flex;
  flex-direction: row;
  width: 100%;
  gap: var(--space-3);
  background: var(--bg-card);
  padding: var(--space-2);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.downloader__form:focus-within {
  border-color: var(--primary);
  box-shadow: var(--shadow-glow-red);
}

.downloader__input-group {
  display: flex;
  flex: 1;
  align-items: center;
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: var(--space-2) var(--space-4);
}

.downloader__input {
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-size: 1rem;
}

.downloader__input::placeholder {
  color: var(--text-tertiary);
}

.downloader__paste-btn {
  padding: var(--space-2);
  font-size: 1.2rem;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.downloader__paste-btn:hover {
  background: var(--bg-elevated);
  transform: scale(1.05);
}

.downloader__submit-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #FFFFFF;
  font-weight: 600;
  border-radius: var(--radius-lg);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), opacity var(--transition-fast);
}

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

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

.downloader__submit-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.downloader__spinner {
  animation: spin 1s linear infinite;
  display: inline-block;
}

.downloader__helper {
  font-size: 0.875rem;
  color: var(--text-tertiary);
}

/* Result Card Container */
.downloader__result {
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  margin-top: var(--space-4);
  box-shadow: var(--shadow-md);
  animation: slideUp var(--transition-base);
}

.result-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.result-card__media {
  width: 100%;
  max-height: 400px;
  object-fit: contain;
  border-radius: var(--radius-lg);
  background: var(--bg-secondary);
}

.result-card__info {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.result-card__title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.result-card__author {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.result-card__actions {
  display: flex;
  flex-direction: column;
  width: 100%;
  gap: var(--space-3);
  margin-top: var(--space-3);
}

.btn-download {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  width: 100%;
  padding: var(--space-4) var(--space-6);
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 1rem;
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
  transition: all var(--transition-base);
}

[data-theme="light"] .btn-download {
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(0, 0, 0, 0.1);
  color: #1A1A1A;
}

/* Shimmer Light Effect Animation */
.btn-download::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 60%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.25),
    transparent
  );
  transform: skewX(-20deg);
  transition: left 0.7s ease;
}

.btn-download:hover::before {
  left: 140%;
}

.btn-download:hover:not(:disabled) {
  transform: translateY(-3px) scale(1.01);
  border-color: var(--primary);
  box-shadow: 0 8px 25px rgba(254, 44, 85, 0.35), var(--shadow-glow-red);
}

.btn-download:active:not(:disabled) {
  transform: translateY(-1px) scale(0.99);
}

/* Variant Glass Buttons */
.btn-download--primary {
  background: linear-gradient(135deg, rgba(254, 44, 85, 0.25) 0%, rgba(217, 35, 72, 0.4) 100%);
  border-color: rgba(254, 44, 85, 0.4);
}

.btn-download--primary:hover:not(:disabled) {
  background: linear-gradient(135deg, rgba(254, 44, 85, 0.45) 0%, rgba(217, 35, 72, 0.6) 100%);
  border-color: var(--primary-light);
}

.btn-download--hd {
  background: linear-gradient(135deg, rgba(37, 244, 238, 0.15) 0%, rgba(27, 196, 190, 0.3) 100%);
  border-color: rgba(37, 244, 238, 0.35);
}

.btn-download--hd:hover:not(:disabled) {
  background: linear-gradient(135deg, rgba(37, 244, 238, 0.35) 0%, rgba(27, 196, 190, 0.5) 100%);
  border-color: var(--accent);
  box-shadow: 0 8px 25px rgba(37, 244, 238, 0.35), var(--shadow-glow-cyan);
}

.btn-download--audio {
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.15) 0%, rgba(37, 99, 235, 0.3) 100%);
  border-color: rgba(59, 130, 246, 0.35);
}

.btn-download--audio:hover:not(:disabled) {
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.35) 0%, rgba(37, 99, 235, 0.5) 100%);
  border-color: var(--info);
  box-shadow: 0 8px 25px rgba(59, 130, 246, 0.35);
}

.btn-download:disabled {
  opacity: 0.6;
  cursor: wait;
  animation: pulse 1.5s infinite;
}

.btn-audio:hover:not(:disabled) {
  box-shadow: var(--shadow-glow-red);
}

.result-card__images-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: var(--space-4);
  width: 100%;
  margin-top: var(--space-3);
}

.result-card__image-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  background: var(--bg-secondary);
  padding: var(--space-2);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

.result-card__image-item img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: var(--radius-sm);
}

.btn-sm {
  padding: var(--space-2) var(--space-3);
  font-size: 0.85rem;
}

/* ------------------------------------------
   8. FEATURES GRID & GLASSMORPHISM
   ------------------------------------------ */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-6);
  width: 100%;
}

.feature-card {
  background: rgba(26, 26, 26, 0.6);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--border);
  padding: var(--space-6);
  border-radius: var(--radius-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  transition: transform var(--transition-base), border-color var(--transition-base), box-shadow var(--transition-base);
}

[data-theme="light"] .feature-card {
  background: rgba(255, 255, 255, 0.8);
}

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

.feature-card__icon {
  font-size: 2rem;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-elevated);
  border-radius: var(--radius-lg);
}

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

.feature-card__desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

/* ------------------------------------------
   9. HISTORY SECTION
   ------------------------------------------ */
.history {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  width: 100%;
}

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

.history__badge {
  font-size: 0.75rem;
  padding: var(--space-1) var(--space-3);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-weight: 500;
}

.history__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.history__empty {
  text-align: center;
  padding: var(--space-8);
  background: var(--bg-secondary);
  border: 1px dashed var(--border);
  border-radius: var(--radius-lg);
  color: var(--text-tertiary);
}

.history__item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  gap: var(--space-4);
  transition: background var(--transition-fast);
}

.history__item:hover {
  background: var(--bg-elevated);
}

.history__item-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  overflow: hidden;
}

.history__item-url {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.history__item-date {
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

.history__item-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.btn-icon {
  padding: var(--space-2);
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.btn-icon:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

/* ------------------------------------------
   10. FAQ ACCORDION STYLES
   ------------------------------------------ */
.faq {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  width: 100%;
}

.faq__item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq__item[open] {
  border-color: var(--primary);
}

.faq__item summary {
  padding: var(--space-4) var(--space-6);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--text-primary);
  cursor: pointer;
  user-select: none;
  position: relative;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq__item summary::-webkit-details-marker {
  display: none;
}

.faq__item summary::after {
  content: "＋";
  font-size: 1.2rem;
  color: var(--text-secondary);
  transition: transform var(--transition-fast);
}

.faq__item[open] summary::after {
  content: "－";
  color: var(--primary);
}

.faq__item p {
  padding: 0 var(--space-6) var(--space-6) var(--space-6);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* ------------------------------------------
   11. FOOTER STYLES
   ------------------------------------------ */
.footer {
  border-top: 1px solid var(--border);
  padding: var(--space-8) var(--space-4);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  text-align: center;
  background: var(--bg-secondary);
  margin-top: auto;
}

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

.footer__links {
  display: flex;
  gap: var(--space-6);
}

.footer__links a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer__links a:hover {
  color: var(--primary);
}

/* ------------------------------------------
   12. TOAST NOTIFICATIONS SYSTEM
   ------------------------------------------ */
.toast-container {
  position: fixed;
  top: var(--space-6);
  right: var(--space-6);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  min-width: 280px;
  max-width: 400px;
  padding: var(--space-4) var(--space-6);
  border-radius: var(--radius-lg);
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  animation: slideInRight var(--transition-base) forwards;
}

.toast--success {
  border-left: 4px solid var(--success);
}

.toast--error {
  border-left: 4px solid var(--error);
}

.toast--warning {
  border-left: 4px solid var(--warning);
}

.toast--info {
  border-left: 4px solid var(--info);
}

/* ------------------------------------------
   13. ANIMATIONS & KEYFRAMES
   ------------------------------------------ */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

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

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(100%); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.03); }
  100% { transform: scale(1); }
}

/* ------------------------------------------
   14. RESPONSIVE MEDIA QUERIES (MOBILE-FIRST)
   ------------------------------------------ */
/* Mobile S / Extra Small (320px) */
@media (max-width: 479px) {
  h1 { font-size: 26px; }
  h2 { font-size: 22px; }
  h3 { font-size: 18px; }
  
  .header {
    padding: var(--space-3) var(--space-4);
  }
  
  .downloader__form {
    flex-direction: column;
    padding: var(--space-3);
  }

  .downloader__submit-btn {
    width: 100%;
  }

  .toast-container {
    left: var(--space-4);
    right: var(--space-4);
    top: var(--space-4);
  }
}

/* Mobile M / Small (480px) */
@media (min-width: 480px) and (max-width: 767px) {
  h1 { font-size: 30px; }
}

/* Tablet (768px) */
@media (min-width: 768px) {
  .hero__title { font-size: 42px; }
}

/* Desktop / Laptop (1024px) */
@media (min-width: 1024px) {
  .hero__title { font-size: 48px; }
}

/* Large Desktop (1440px) */
@media (min-width: 1440px) {
  .main { max-width: 1280px; }
}

/* ------------------------------------------
   15. PRINT STYLESHEET
   ------------------------------------------ */
@media print {
  body {
    background: #FFFFFF !important;
    color: #000000 !important;
  }
  .header, .footer, .downloader__form, .toast-container, .header__theme-toggle {
    display: none !important;
  }
  .main {
    max-width: 100%;
    padding: 0;
  }
}