/* ===================================
   Base Variables
   =================================== */
:root {
  --bg-gradient-start: #000000;
  --bg-gradient-end: #5788fe;
  --filter-color: #fe5757;
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.8);
  --border-color: rgba(255, 255, 255, 0.3);
  --button-hover-bg: #ff7f00;
  --progress-bg: rgba(255, 255, 255, 0.2);
  --progress-fill: #ff7f00;
  --player-bg: rgba(255, 255, 255, 0.1);
  --player-hover-bg: rgba(255, 255, 255, 0.15);
  --toast-bg: rgba(0, 0, 0, 0.9);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  --focus-ring-color: #ff7f00;
}

[data-theme='dark'] {
  --bg-gradient-start: #0a0a0a;
  --bg-gradient-end: #1a237e;
  --filter-color: #c62828;
  --text-primary: #e0e0e0;
  --text-secondary: rgba(224, 224, 224, 0.7);
}

[data-theme='light'] {
  --bg-gradient-start: #f5f5f5;
  --bg-gradient-end: #90caf9;
  --filter-color: #ff8a80;
  --text-primary: #212121;
  --text-secondary: rgba(33, 33, 33, 0.7);
  --border-color: rgba(33, 33, 33, 0.2);
  --progress-bg: rgba(33, 33, 33, 0.1);
  --player-bg: rgba(33, 33, 33, 0.05);
  --player-hover-bg: rgba(33, 33, 33, 0.1);
  --toast-bg: rgba(255, 255, 255, 0.95);
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    --bg-gradient-start: #f5f5f5;
    --bg-gradient-end: #90caf9;
    --filter-color: #ff8a80;
    --text-primary: #212121;
    --text-secondary: rgba(33, 33, 33, 0.7);
    --border-color: rgba(33, 33, 33, 0.2);
    --progress-bg: rgba(33, 33, 33, 0.1);
    --player-bg: rgba(33, 33, 33, 0.05);
    --player-hover-bg: rgba(33, 33, 33, 0.1);
    --toast-bg: rgba(255, 255, 255, 0.95);
  }
}

/* ===================================
   Global Reset & Typography
   =================================== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  height: 100%;
}

html {
  font-size: clamp(15px, 1.6vw, 18px);
}

body {
  margin: 0;
  width: 100%;
  min-height: 100%;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial,
    'Noto Sans', 'Liberation Sans', sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji',
    'Segoe UI Symbol', 'Noto Color Emoji';
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: linear-gradient(to bottom, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
  color: var(--text-primary);
  transition: background var(--transition-slow), color var(--transition-normal);
}

/* ===================================
   Accessibility Helpers
   =================================== */
.skip-link {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 10001;
  transform: translateY(-100%);
  background: #000;
  color: #fff;
  padding: 0.75rem 1.25rem;
  font-weight: 600;
  text-decoration: none;
  transition: transform 0.2s ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.noscript-message {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  background: rgba(0, 0, 0, 0.85);
  color: #fff;
  font-size: 1.1rem;
  text-align: center;
  z-index: 12000;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

*:focus-visible {
  outline: 2px solid var(--focus-ring-color);
  outline-offset: 2px;
}

button:focus-visible {
  outline: 2px solid var(--focus-ring-color);
  outline-offset: 2px;
}

.hidden {
  display: none !important;
}

/* ===================================
   Background Layers
   =================================== */
.filter {
  position: absolute;
  inset: 0;
  background: var(--filter-color);
  mix-blend-mode: overlay;
  pointer-events: none;
  animation: colorChange 30s ease-in-out infinite;
  animation-fill-mode: both;
  will-change: opacity;
}

.landscape {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-size: 1000px 250px;
  background-repeat: repeat-x;
  background-position: center bottom;
  pointer-events: none;
}

@keyframes colorChange {
  0%,
  100% {
    opacity: 0;
  }

  50% {
    opacity: 0.9;
  }
}

/* ===================================
   Main Content
   =================================== */
.content {
  position: absolute;
  left: 50%;
  top: 45%;
  transform: translate(-50%, -50%);
  text-align: center;
  color: var(--text-primary);
  user-select: none;
  z-index: 10;
  max-width: min(90%, 720px);
  transition: color var(--transition-normal);
}

.content .title {
  margin: 15px 0;
  font-size: clamp(2rem, 5vw, 2.5rem);
  letter-spacing: 4px;
  color: var(--text-primary);
  font-weight: 300;
}

.content .hr {
  width: 50%;
  margin: 20px auto;
  border: none;
  border-top: 1px solid var(--text-primary);
  height: 1px;
  opacity: 0.8;
}

.hitokoto {
  margin: 25px auto;
  padding: 0 20px;
  max-width: 600px;
}

.hitokoto-text {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  color: var(--text-secondary);
  margin-bottom: 8px;
  line-height: 1.6;
  font-style: italic;
}

.hitokoto-from {
  font-size: 0.875rem;
  color: var(--text-secondary);
  opacity: 0.7;
}

.datetime {
  margin: 20px 0;
  font-size: 1.125rem;
  color: var(--text-secondary);
}

.datetime .date {
  margin-bottom: 5px;
  font-weight: 500;
}

.datetime .time {
  font-size: clamp(1.25rem, 4vw, 1.75rem);
  font-weight: 300;
  letter-spacing: 2px;
  font-variant-numeric: tabular-nums;
}

.weather {
  margin: 20px 0;
  font-size: 1rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.weather-icon {
  font-size: 1.5rem;
}

.weather-temp {
  font-weight: 600;
}

/* ===================================
   Progress Indicators
   =================================== */
.progress-bars {
  margin: 30px auto;
  max-width: 500px;
  padding: 0 20px;
}

.progress-item {
  margin: 15px 0;
  display: flex;
  align-items: center;
  gap: 10px;
}

.progress-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  min-width: 70px;
  text-align: left;
}

.progress-bar {
  flex: 1;
  height: 6px;
  background: var(--progress-bg);
  border-radius: 10px;
  overflow: hidden;
  backdrop-filter: blur(10px);
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--progress-fill), var(--button-hover-bg));
  border-radius: 10px;
  transition: width var(--transition-normal);
  will-change: width;
}

.progress-value {
  font-size: 0.875rem;
  color: var(--text-secondary);
  min-width: 45px;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

/* ===================================
   Navigation
   =================================== */
.cover-navigation {
  margin: 30px;
}

nav {
  display: inline-block;
  position: relative;
}

.navigation {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 15px;
  list-style-type: none;
  margin: 0;
  padding: 0;
}

.navigation__item {
  display: inline-block;
}

.navigation__item a,
.navigation__item button {
  position: relative;
  color: var(--text-primary);
  opacity: 0.8;
  transition: all var(--transition-normal);
  padding: 10px 20px;
  border: 1px solid var(--border-color);
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 1px;
  text-decoration: none;
  display: inline-block;
  backdrop-filter: blur(10px);
  background: transparent;
  cursor: pointer;
}

.navigation__item button {
  font: inherit;
}

.navigation__item a:hover,
.navigation__item a:focus-visible,
.navigation__item button:hover,
.navigation__item button:focus-visible {
  color: var(--text-primary);
  background: var(--button-hover-bg);
  border-color: var(--button-hover-bg);
  opacity: 1;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* ===================================
   Theme Toggle
   =================================== */
.site-tools {
  position: relative;
  z-index: 100;
}

.theme-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  display: flex;
  gap: 8px;
  background: var(--player-bg);
  padding: 8px;
  border-radius: 24px;
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.theme-btn {
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  position: relative;
}

.theme-btn:hover {
  background: var(--player-hover-bg);
  color: var(--text-primary);
  transform: scale(1.1);
}

.theme-btn.active {
  background: var(--button-hover-bg);
  color: #fff;
}

.theme-btn.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background: var(--button-hover-bg);
  border-radius: 2px;
}

/* ===================================
   Music Player
   =================================== */
.music-player {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--player-bg);
  backdrop-filter: blur(20px);
  padding: 15px 20px;
  box-shadow: var(--shadow-lg);
  z-index: 100;
  transition: all var(--transition-normal);
}

.music-info {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
}

.music-cover {
  width: 50px;
  height: 50px;
  background: var(--progress-bg);
  border-radius: 8px;
  flex-shrink: 0;
  background-size: cover;
  background-position: center;
}

.music-details {
  flex: 1;
  text-align: left;
  min-width: 0;
}

.music-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.music-time {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 4px;
  font-variant-numeric: tabular-nums;
}

.music-time .separator {
  margin: 0 4px;
}

.music-progress {
  margin: 10px 0;
  cursor: pointer;
  padding: 8px 0;
}

.music-progress-bar {
  width: 100%;
  height: 4px;
  background: var(--progress-bg);
  border-radius: 2px;
  overflow: hidden;
  position: relative;
  transition: height var(--transition-fast);
}

.music-progress-fill {
  height: 100%;
  background: var(--progress-fill);
  border-radius: 2px;
  transition: width 0.1s linear;
  will-change: width;
}

.music-progress:hover .music-progress-bar {
  height: 6px;
}

.music-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.music-btn {
  width: 44px;
  height: 44px;
  border: none;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  position: relative;
}

.music-btn:hover {
  background: var(--player-hover-bg);
  transform: scale(1.1);
}

.music-btn.play-btn {
  width: 56px;
  height: 56px;
  background: var(--button-hover-bg);
  color: #fff;
}

.music-btn.play-btn:hover {
  transform: scale(1.15);
  box-shadow: var(--shadow-md);
}

.music-btn svg {
  pointer-events: none;
}

.volume-control {
  position: absolute;
  bottom: 100%;
  right: 0;
  margin-bottom: 10px;
  padding: 12px;
  background: var(--toast-bg);
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(20px);
}

.volume-slider {
  width: 100px;
  height: 4px;
  border-radius: 2px;
  background: var(--progress-bg);
  outline: none;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
}

.volume-slider::-webkit-slider-thumb {
  appearance: none;
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--button-hover-bg);
  cursor: pointer;
  transition: transform var(--transition-fast);
}

.volume-slider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.volume-slider::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--button-hover-bg);
  cursor: pointer;
  border: none;
  transition: transform var(--transition-fast);
}

.volume-slider::-moz-range-thumb:hover {
  transform: scale(1.2);
}

/* ===================================
   Network & Toast Notifications
   =================================== */
.network-status {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(244, 67, 54, 0.95);
  color: #fff;
  padding: 12px 24px;
  border-radius: 24px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  backdrop-filter: blur(10px);
  animation: slideDown var(--transition-normal);
}

.network-status[hidden] {
  display: none;
}

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

  to {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }
}

.toast {
  position: fixed;
  top: 20px;
  right: 20px;
  min-width: 300px;
  max-width: 400px;
  background: var(--toast-bg);
  color: var(--text-primary);
  padding: 16px 20px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.9rem;
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  backdrop-filter: blur(20px);
  animation: slideIn var(--transition-normal);
}

.toast[hidden] {
  display: none;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(100px);
  }

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

.toast-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.toast-message {
  flex: 1;
}

.toast-close {
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: 4px;
  font-size: 1.5rem;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.toast-close:hover {
  background: var(--player-hover-bg);
  color: var(--text-primary);
}

/* ===================================
   Loading Screen
   =================================== */
.loading-screen {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(to bottom, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
  z-index: 10000;
  transition: opacity var(--transition-slow);
}

.loading-screen.hidden {
  opacity: 0;
  pointer-events: none;
}

.loader {
  width: 48px;
  height: 48px;
  border: 3px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  border-top-color: #fff;
  animation: spin 1s ease-in-out infinite;
}

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

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 768px) {
  .content {
    top: 40%;
  }

  .content .title {
    font-size: 2rem;
    letter-spacing: 2px;
  }

  .hitokoto,
  .progress-bars {
    max-width: 90%;
  }

  .progress-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .progress-label {
    min-width: auto;
  }

  .progress-bar {
    width: 100%;
  }

  .navigation {
    gap: 10px;
  }

  .navigation__item a,
  .navigation__item button {
    padding: 8px 16px;
    font-size: 0.85rem;
  }

  .theme-toggle {
    top: 10px;
    right: 10px;
    padding: 6px;
    gap: 6px;
  }

  .theme-btn {
    width: 36px;
    height: 36px;
  }

  .theme-btn svg {
    width: 18px;
    height: 18px;
  }

  .music-player {
    padding: 12px 15px;
  }

  .toast {
    right: 10px;
    left: 10px;
    min-width: auto;
  }
}

@media (max-width: 480px) {
  .content .title {
    font-size: 1.75rem;
  }

  .datetime .time {
    font-size: 1.25rem;
  }

  .music-controls {
    gap: 8px;
  }

  .music-btn {
    width: 40px;
    height: 40px;
  }

  .music-btn.play-btn {
    width: 48px;
    height: 48px;
  }
}

@media print {
  .filter,
  .landscape,
  .theme-toggle,
  .music-player,
  .network-status,
  .toast,
  .loading-screen {
    display: none !important;
  }

  body {
    background: #ffffff;
    color: #000000;
  }
}

/* ===================================
   Motion & Contrast Preferences
   =================================== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .filter {
    animation: none !important;
  }
}

@media (prefers-contrast: high) {
  :root {
    --border-color: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.95);
  }

  .navigation__item a,
  .navigation__item button {
    border-width: 2px;
  }
}