/* ===== CSS VARIABLES ===== */
:root {
  /* Colors */
  --color-primary: #6366f1;
  --color-primary-hover: #5855eb;
  --color-primary-light: #a5b4fc;
  --color-secondary: #64748b;
  --color-success: #10b981;
  --color-success-hover: #059669;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --color-error-hover: #dc2626;
  
  /* Background Colors */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --bg-glass: rgba(30, 41, 59, 0.8);
  --bg-glass-light: rgba(51, 65, 85, 0.6);
  --bg-overlay: rgba(15, 23, 42, 0.95);
  
  /* Text Colors */
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-inverse: #1e293b;
  
  /* Border Colors */
  --border-primary: #475569;
  --border-secondary: #64748b;
  --border-focus: var(--color-primary);
  --border-error: var(--color-error);
  
  /* Typography */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 0.75rem;
  --spacing-lg: 1rem;
  --spacing-xl: 1.5rem;
  --spacing-2xl: 2rem;
  --spacing-3xl: 3rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-glass: 0 8px 32px rgba(0, 0, 0, 0.3);
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  /* Z-Index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal: 1040;
  --z-popover: 1050;
  --z-tooltip: 1060;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--text-primary);
  background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== ACCESSIBILITY ===== */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--color-primary);
  color: white;
  padding: 8px;
  text-decoration: none;
  border-radius: var(--radius-md);
  z-index: var(--z-tooltip);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 6px;
}

/* Focus styles for better accessibility */
*:focus {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

/* ===== LAYOUT ===== */
.main-container {
  display: grid;
  grid-template-columns: 320px 1fr;
  min-height: 100vh;
  gap: 0;
}

.sidebar {
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  border-right: 1px solid var(--border-primary);
  padding: var(--spacing-xl);
  overflow-y: auto;
  position: sticky;
  top: 0;
  height: 100vh;
  box-shadow: var(--shadow-glass);
}

.content {
  padding: var(--spacing-2xl);
  overflow-y: auto;
  max-width: 100%;
}

/* ===== TYPOGRAPHY ===== */
h1 {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-sm);
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
}

.section-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--text-primary);
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--border-primary);
}

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

.help-text {
  display: block;
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  margin-top: var(--spacing-xs);
  line-height: var(--line-height-normal);
}

/* ===== SECTIONS ===== */
.sidebar section {
  margin-bottom: var(--spacing-2xl);
  padding-bottom: var(--spacing-xl);
  border-bottom: 1px solid var(--border-primary);
}

.sidebar section:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

/* ===== FORMS ===== */
.form-group {
  margin-bottom: var(--spacing-xl);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

input[type="text"],
input[type="password"] {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--bg-glass-light);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: var(--font-size-sm);
  font-family: var(--font-family-primary);
  transition: all var(--transition-fast);
  backdrop-filter: blur(10px);
}

input[type="text"]:focus,
input[type="password"]:focus {
  border-color: var(--border-focus);
  background: var(--bg-secondary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

input[type="text"]:invalid,
input[type="password"]:invalid {
  border-color: var(--border-error);
}

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

/* ===== BUTTONS ===== */
button {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Primary Button */
.generate-btn,
.save-btn {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-hover));
  color: white;
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-weight: var(--font-weight-semibold);
  box-shadow: var(--shadow-md);
}

.generate-btn:hover,
.save-btn:hover {
  background: linear-gradient(135deg, var(--color-primary-hover), var(--color-primary));
  box-shadow: var(--shadow-lg);
  transform: translateY(-1px);
}

.generate-btn:active,
.save-btn:active {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

/* Action Buttons */
.action-btn {
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-fast);
}

.action-btn.secondary {
  background: var(--bg-glass);
  color: var(--text-primary);
  border: 1px solid var(--border-primary);
  backdrop-filter: blur(10px);
}

.action-btn.secondary:hover {
  background: var(--bg-secondary);
  border-color: var(--border-secondary);
  transform: translateY(-1px);
}

.action-btn.success {
  background: linear-gradient(135deg, var(--color-success), var(--color-success-hover));
  color: white;
  box-shadow: var(--shadow-md);
}

.action-btn.success:hover {
  background: linear-gradient(135deg, var(--color-success-hover), var(--color-success));
  box-shadow: var(--shadow-lg);
  transform: translateY(-1px);
}

.btn-shortcut {
  font-size: var(--font-size-xs);
  opacity: 0.7;
  font-weight: var(--font-weight-normal);
  margin-left: var(--spacing-sm);
}

/* ===== OUTPUT AREA ===== */
.output {
  background: var(--bg-glass);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-2xl);
  min-height: 200px;
  max-height: 500px;
  overflow-y: auto;
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
  color: var(--text-primary);
  white-space: pre-wrap;
  word-wrap: break-word;
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-md);
  margin-bottom: var(--spacing-xl);
}

.output:empty::before {
  content: "Generated songtext will appear here...";
  color: var(--text-muted);
  font-style: italic;
  font-family: var(--font-family-primary);
}

/* ===== ACTIONS ===== */
.actions {
  display: flex;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
  margin-bottom: var(--spacing-lg);
}

.action-help {
  display: none;
}

/* ===== LOADING ===== */
.loading {
  display: none;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-lg);
  padding: var(--spacing-2xl);
  background: var(--bg-glass);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-xl);
  backdrop-filter: blur(10px);
}

.loading.show {
  display: flex;
}

.loading-spinner {
  width: 24px;
  height: 24px;
  border: 3px solid var(--border-primary);
  border-top: 3px solid var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

.loading-text {
  color: var(--text-secondary);
  font-weight: var(--font-weight-medium);
}

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

/* ===== MODEL LIST ===== */
.model-list {
  max-height: 300px;
  overflow-y: auto;
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  background: var(--bg-glass-light);
  backdrop-filter: blur(10px);
}

.model-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) var(--spacing-lg);
  border-bottom: 1px solid var(--border-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.model-item:last-child {
  border-bottom: none;
}

.model-item:hover {
  background: var(--bg-secondary);
}

.model-item.selected {
  background: var(--color-primary);
  color: white;
}

.model-info {
  flex: 1;
}

.model-name {
  font-weight: var(--font-weight-medium);
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.model-id {
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  font-family: var(--font-family-mono);
}

.fav-btn {
  background: none;
  border: none;
  font-size: var(--font-size-lg);
  cursor: pointer;
  padding: var(--spacing-xs);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

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

.fav-btn.favorited {
  color: var(--color-warning);
}

/* ===== SEARCH INFO ===== */
.search-info {
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  margin-bottom: var(--spacing-sm);
  padding: var(--spacing-sm);
  background: var(--bg-glass-light);
  border-radius: var(--radius-sm);
  text-align: center;
}

/* ===== FAVORITES ===== */
.favorites-list {
  max-height: 200px;
  overflow-y: auto;
}

/* ===== HISTORY ===== */
.history-list {
  max-height: 250px;
  overflow-y: auto;
}

.history-item {
  background: var(--bg-glass-light);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  backdrop-filter: blur(10px);
}

.history-item:hover {
  background: var(--bg-secondary);
  border-color: var(--border-secondary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.history-item:last-child {
  margin-bottom: 0;
}

.history-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-sm);
}

.history-theme {
  font-weight: var(--font-weight-medium);
  color: var(--text-primary);
}

.history-genre {
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  background: var(--bg-tertiary);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
}

.history-timestamp {
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  font-family: var(--font-family-mono);
}

.history-preview {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  line-height: var(--line-height-normal);
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}

/* ===== NOTIFICATIONS ===== */
.notifications {
  position: fixed;
  top: var(--spacing-xl);
  right: var(--spacing-xl);
  z-index: var(--z-tooltip);
  max-width: 400px;
}

.notification {
  background: var(--bg-glass);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
  backdrop-filter: blur(20px);
  box-shadow: var(--shadow-xl);
  animation: slideIn 0.3s ease-out;
  position: relative;
  overflow: hidden;
}

.notification::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-primary);
}

.notification.success::before {
  background: var(--color-success);
}

.notification.error::before {
  background: var(--color-error);
}

.notification.warning::before {
  background: var(--color-warning);
}

.notification-content {
  color: var(--text-primary);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-normal);
}

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

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 1024px) {
  .main-container {
    grid-template-columns: 280px 1fr;
  }
  
  .sidebar {
    padding: var(--spacing-lg);
  }
  
  .content {
    padding: var(--spacing-xl);
  }
}

@media (max-width: 768px) {
  .main-container {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
  }
  
  .sidebar {
    position: static;
    height: auto;
    max-height: 50vh;
    border-right: none;
    border-bottom: 1px solid var(--border-primary);
  }
  
  .form-row {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }
  
  .actions {
    flex-direction: column;
  }
  
  .notifications {
    left: var(--spacing-lg);
    right: var(--spacing-lg);
    max-width: none;
  }
}

@media (max-width: 480px) {
  .sidebar {
    padding: var(--spacing-md);
  }
  
  .content {
    padding: var(--spacing-lg);
  }
  
  h1 {
    font-size: var(--font-size-2xl);
  }
  
  .generate-btn,
  .save-btn {
    padding: var(--spacing-md) var(--spacing-xl);
  }
  
  .output {
    padding: var(--spacing-lg);
    max-height: 300px;
  }
}

/* ===== ACCESSIBILITY IMPROVEMENTS ===== */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media (prefers-contrast: high) {
  :root {
    --border-primary: #ffffff;
    --border-secondary: #ffffff;
    --text-primary: #ffffff;
    --text-secondary: #ffffff;
  }
}

/* ===== PRINT STYLES ===== */
@media print {
  .sidebar,
  .actions,
  .loading,
  .notifications {
    display: none !important;
  }
  
  .main-container {
    grid-template-columns: 1fr;
  }
  
  .output {
    background: white;
    color: black;
    border: 1px solid black;
    box-shadow: none;
  }
}