/* ============================================
   CSS Variables - Production Ready
   ============================================ */

:root {
  /* Color System - Balanced Palette */
  --indigo: #4158D0;
  --cyan: #47C7F2;
  --slate: #0E1525;
  --violet: #A06AF9;
  
  /* Text Colors */
  --text: #e9edf5;
  --muted: #c7ccda;
  
  /* Borders & Glass */
  --border: rgba(255, 255, 255, 0.12);
  
  /* Accent Colors (single accent system) */
  --accent-1: #6ea8ff;
  --accent-2: #7ae0ff;
  
  /* Legacy compatibility */
  --color-text-primary: var(--text);
  --color-text-secondary: var(--muted);
  --color-text-tertiary: rgba(199, 204, 218, 0.6);
  
  /* Glass Effect */
  --glass-bg: rgba(255, 255, 255, 0.06);
  --glass-border: var(--border);
  --glass-highlight: rgba(255, 255, 255, 0.22);
  --glass-blur: 18px;
  --glass-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
  
  /* Spacing */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 32px;
  --space-xl: 48px;
  --space-2xl: 64px;
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'SF Pro Display', sans-serif;
  --font-size-xs: 13px;
  --font-size-sm: 14px;
  --font-size-base: 16px;
  --font-size-lg: 18px;
  --font-size-xl: 24px;
  --font-size-2xl: 32px;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --line-height-base: 1.6;
  
  /* Layout */
  --container-max-width: 880px;
  --container-padding: var(--space-md);
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 120ms ease;
  --transition-base: 150ms ease;
  --transition-slow: 180ms ease;
  
  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-lg: var(--glass-shadow);
  
  /* Accessibility */
  --hit-target-min: 44px;
  --contrast-ratio: 4.5;
}

/* ============================================
   Reset & Base Styles
   ============================================ */

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

html {
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-base);
  color: var(--text);
  background:
    radial-gradient(circle at 20% 20%, rgba(58, 141, 255, 0.25), transparent 60%),
    radial-gradient(circle at 80% 30%, rgba(165, 109, 255, 0.25), transparent 70%),
    radial-gradient(circle at 50% 100%, rgba(255, 182, 193, 0.5), transparent 80%),
    linear-gradient(135deg, #0D1022 0%, #0F1633 100%);
  background-attachment: fixed;
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  animation: gentleShift 30s ease-in-out infinite;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: radial-gradient(60% 40% at 50% -20%, rgba(255, 255, 255, 0.06), transparent 80%);
  pointer-events: none;
  z-index: 0;
}

body::after {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='140' height='140'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='2'/></filter><rect width='100%' height='100%' filter='url(%23n)' opacity='.035'/></svg>");
}

@keyframes gentleShift {
  0%, 100% {
    filter: hue-rotate(0deg);
  }
  50% {
    filter: hue-rotate(10deg);
  }
}

@media (prefers-reduced-motion: reduce) {
  body {
    animation: none;
  }
}

/* ============================================
   Background with Gradients & Grain
   ============================================ */

.background {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  overflow: hidden;
}


/* ============================================
   Container & Layout
   ============================================ */

.container {
  position: relative;
  z-index: 1;
  max-width: 900px;
  margin: 24px auto 96px;
  padding: 0 20px;
  min-height: calc(100vh - 120px);
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: center;
}

/* ============================================
   Header
   ============================================ */

.header {
  text-align: center;
  margin-bottom: var(--space-lg);
  animation: fadeInUp 400ms ease-out;
}

.headline {
  font-size: 30px;
  font-weight: 600;
  letter-spacing: 0.2px;
  margin-bottom: var(--space-xs);
  color: var(--text);
}

.subtitle {
  font-size: 16px;
  color: rgba(220, 230, 255, 0.75);
  font-weight: var(--font-weight-normal);
}

/* ============================================
   Glass Card
   ============================================ */

.glass-card {
  width: 100%;
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(18px) saturate(120%);
  -webkit-backdrop-filter: blur(18px) saturate(120%);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-xl);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.25),
    0 10px 30px rgba(0, 0, 0, 0.4);
  padding: var(--space-lg);
  padding-top: calc(var(--space-lg) + 8px);
  position: relative;
  animation: fadeInUp 500ms ease-out 100ms both;
}

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

/* ============================================
   Textarea
   ============================================ */

.input-container {
  position: relative;
  margin-bottom: var(--space-lg);
}

.textarea {
  width: 100%;
  min-height: 200px;
  padding: var(--space-md);
  background: rgba(255, 255, 255, 0.03);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  color: var(--text);
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.6;
  letter-spacing: 0.2px;
  resize: vertical;
  transition: all 0.2s ease;
  outline: none;
}

.file-upload-area {
  display: block;
  width: 100%;
  min-height: 52px;
  padding: var(--space-sm) var(--space-lg);
  background: rgba(255, 255, 255, 0.02);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  text-align: center;
  cursor: pointer;
  transition: all 0.2s ease;
  margin-top: var(--space-sm);
}

.file-upload-area:hover,
.file-upload-area.drag-over {
  border-color: var(--accent-1);
  background: rgba(110, 168, 255, 0.05);
}

.file-upload-area.has-files {
  display: none;
}

.file-upload-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.upload-icon {
  width: 20px;
  height: 20px;
  color: var(--muted);
  margin-bottom: 2px;
}

.upload-text {
  color: var(--text);
  font-size: var(--font-size-sm);
  margin: 0;
}

.upload-link {
  color: var(--accent-1);
  text-decoration: underline;
  cursor: pointer;
}

.upload-hint {
  color: var(--muted);
  font-size: var(--font-size-xs);
  margin: 0;
  opacity: 0.7;
}

.file-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-top: var(--space-sm);
}

.file-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-xs) var(--space-sm);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  color: var(--text);
}

.file-item-info {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  flex: 1;
  min-width: 0;
}

.file-item-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-item-size {
  color: var(--muted);
  font-size: var(--font-size-xs);
  margin-left: var(--space-xs);
}

.file-item-remove {
  background: none;
  border: none;
  color: var(--muted);
  cursor: pointer;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  transition: all 0.2s ease;
  font-size: 18px;
  line-height: 1;
}

.file-item-remove:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.1);
}

.textarea::placeholder {
  color: var(--muted);
  opacity: 0.6;
}

.textarea:focus {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(150, 200, 255, 0.3);
  box-shadow: 0 0 6px rgba(100, 180, 255, 0.25);
  transition: all 0.2s ease;
}

.textarea:focus-visible {
  outline: 2px solid #9ecbff;
  outline-offset: 3px;
}

/* ============================================
   Controls Row
   ============================================ */

.controls-row {
  display: flex;
  gap: var(--space-lg);
  margin-bottom: 28px;
  flex-wrap: wrap;
}

.actions {
  display: flex;
  gap: 12px;
  justify-content: flex-end;
  margin-top: 24px;
}

.controls-left,
.controls-right {
  flex: 1;
  min-width: 280px;
}

.control-label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.tone-pill-custom {
  border: 1px dashed var(--border);
}

.tone-pill-custom:hover {
  border-style: solid;
  border-color: var(--accent-2);
}

.tone-pill-custom[aria-pressed="true"],
.tone-pill-custom.active {
  border-style: solid;
  border-color: var(--accent-2);
  background: rgba(122, 200, 255, 0.1);
}

.tone-input-container {
  margin-top: var(--space-sm);
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  animation: fadeInUp 0.2s ease-out;
}

.tone-input-container.hidden {
  display: none;
}

.tone-input {
  flex: 1;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 10px;
  padding: 8px 12px;
  font-size: 14px;
  color: #e4e9f3;
  outline: none;
  transition: all 0.2s ease;
  font-family: var(--font-family);
}

.tone-input::placeholder {
  color: var(--muted);
  opacity: 0.6;
}

.tone-input:focus {
  border-color: #8ebdff;
  box-shadow: 0 0 6px rgba(136, 190, 255, 0.3);
  background: rgba(255, 255, 255, 0.08);
}

.tone-input:focus-visible {
  outline: 2px solid #9ecbff;
  outline-offset: 3px;
}

.tone-input-clear {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 8px;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  cursor: pointer;
  font-size: 16px;
  transition: all 0.2s ease;
  outline: none;
  flex-shrink: 0;
}

.tone-input-clear:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text);
  border-color: rgba(255, 255, 255, 0.2);
}

.tone-input-clear:focus-visible {
  outline: 2px solid #9ecbff;
  outline-offset: 2px;
}

/* ============================================
   Tone Pills (Multi-select)
   ============================================ */

.tone-pills {
  display: flex;
  gap: var(--space-xs);
  flex-wrap: wrap;
}

.tone-pill {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-sm);
  background: rgba(255, 255, 255, 0.07);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  color: var(--muted);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  cursor: pointer;
  transition: all var(--transition-base);
  outline: none;
  min-height: var(--hit-target-min);
  position: relative;
}

.tone-pill:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--glass-highlight);
  color: var(--text);
  transform: translateY(-1px);
}

.tone-pill:focus-visible {
  outline: 2px solid #9ecbff;
  outline-offset: 3px;
}

.tone-pill[aria-pressed="true"],
.tone-pill.active {
  box-shadow: 
    0 0 0 2px color-mix(in oklab, var(--accent-2) 60%, white 0%) inset,
    inset 0 1px 0 rgba(255, 255, 255, 0.25);
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--accent-2);
  color: var(--text);
}

.tone-icon {
  font-size: var(--font-size-base);
  line-height: 1;
}

/* ============================================
   Slider
   ============================================ */

.slider-wrapper {
  position: relative;
  margin-bottom: var(--space-sm);
}

.slider-value {
  display: inline-block;
  margin-left: var(--space-xs);
  color: var(--color-text-primary);
  font-weight: var(--font-weight-semibold);
}

.slider-track-container {
  position: relative;
  height: 4px;
  margin-bottom: var(--space-xs);
}

.slider-track-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.16);
}

.slider-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--accent-1), var(--accent-2));
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
  pointer-events: none;
}

.slider {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  margin: 0;
  border-radius: var(--radius-full);
  background: transparent;
  outline: none;
  -webkit-appearance: none;
  appearance: none;
  cursor: pointer;
  z-index: 2;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, #fff, #dbe7ff 60%, #b9d9ff 100%);
  cursor: grab;
  border: 3px solid rgba(255, 255, 255, 0.8);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.35);
  transition: all var(--transition-base);
}

.slider::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

.slider::-webkit-slider-thumb:active {
  cursor: grabbing;
  transform: scale(1.1);
}

.slider::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, #fff, #dbe7ff 60%, #b9d9ff 100%);
  cursor: grab;
  border: 3px solid rgba(255, 255, 255, 0.8);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.35);
  transition: all var(--transition-base);
}

.slider::-moz-range-thumb:hover {
  transform: scale(1.1);
}

.slider::-moz-range-thumb:active {
  cursor: grabbing;
  transform: scale(1.1);
}

.slider:focus-visible {
  outline: 2px solid #9ecbff;
  outline-offset: 3px;
}

.slider-ticks {
  display: flex;
  justify-content: space-between;
  padding: 0 10px;
  margin-top: var(--space-xs);
  opacity: 0.6;
  transition: opacity var(--transition-base);
  pointer-events: none;
}

.slider-wrapper:hover .slider-ticks {
  opacity: 1;
}

.slider-ticks .tick {
  width: 2px;
  height: 8px;
  background: rgba(255, 255, 255, 0.4);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
}

.slider-wrapper:hover .slider-ticks .tick {
  background: rgba(255, 255, 255, 0.6);
  height: 10px;
}

.simplicity-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.5;
  margin-top: var(--space-sm);
  padding: var(--space-sm);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.05);
  transition: all var(--transition-base);
}

/* ============================================
   CTA Button
   ============================================ */

.cta-button {
  padding: 10px 18px;
  min-width: 160px;
  border-radius: 12px;
  background: linear-gradient(90deg, #7EC8FF, #A977FF);
  color: #0b0f1c;
  font-family: var(--font-family);
  font-size: 15px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  outline: none;
  box-shadow: 0 4px 16px rgba(122, 180, 255, 0.4);
  min-height: var(--hit-target-min);
  position: relative;
  overflow: hidden;
}

.cta-button--wide {
  width: 220px;
}


.cta-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -200px;
  width: 200px;
  height: 100%;
  background: linear-gradient(90deg, rgba(255, 255, 255, 0.2) 25%, rgba(255, 255, 255, 0.5) 50%, rgba(255, 255, 255, 0.2) 75%);
  background-size: 400px 100%;
  transition: left var(--transition-slow);
}

.cta-button.loading::before {
  animation: shimmer 1.6s infinite;
}

.cta-button:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 6px 22px rgba(122, 180, 255, 0.6);
}

.cta-button:active:not(:disabled) {
  transform: translateY(0);
}

.cta-button:focus-visible {
  outline: 2px solid #9ecbff;
  outline-offset: 3px;
}

.cta-button:hover:not(:disabled)::before {
  left: 100%;
}

.cta-button:active:not(:disabled) {
  transform: translateY(0);
}

.cta-button:focus-visible {
  box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.3);
}

.cta-button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* ============================================
   Output Area
   ============================================ */

.output-area {
  margin-top: var(--space-lg);
  animation: fadeIn 300ms ease-out;
}

.output-area.hidden {
  display: none;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.output-card {
  background: rgba(255, 255, 255, 0.03);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
  box-shadow: var(--shadow-sm);
}

.output-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-md);
}

.output-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
}

.copy-button {
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: var(--space-xs);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-base);
  outline: none;
  display: flex;
  align-items: center;
  justify-content: center;
  width: var(--hit-target-min);
  height: var(--hit-target-min);
}

.copy-button:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--glass-highlight);
  color: var(--color-text-primary);
}

.copy-button:focus-visible {
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.3);
}

.output-text {
  color: var(--color-text-primary);
  line-height: var(--line-height-base);
  font-size: var(--font-size-base);
  white-space: pre-wrap;
  word-wrap: break-word;
}

/* ============================================
   Loading Area
   ============================================ */

.loading-area {
  margin-top: var(--space-lg);
  text-align: center;
}

.loading-area.hidden {
  display: none;
}

.shimmer {
  width: 100%;
  height: 120px;
  background: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0.05) 0%,
    rgba(255, 255, 255, 0.1) 50%,
    rgba(255, 255, 255, 0.05) 100%
  );
  background-size: 200% 100%;
  animation: shimmer 2s ease-in-out infinite;
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-md);
}

@keyframes shimmer {
  0% {
    left: -200px;
  }
  100% {
    left: calc(100% + 200px);
  }
}

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

/* ============================================
   Toast
   ============================================ */

.toast {
  position: fixed;
  bottom: var(--space-lg);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  color: var(--color-text-primary);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transition: all var(--transition-slow);
  z-index: 1000;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast.hidden {
  display: none;
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 768px) {
  :root {
    --container-padding: var(--space-sm);
    --font-size-2xl: 28px;
  }
  
  .container {
    padding: var(--space-md) var(--space-sm);
  }
  
  .glass-card {
    padding: var(--space-md);
  }
  
  .controls-row {
    flex-direction: column;
    gap: var(--space-md);
  }
  
  .controls-left,
  .controls-right {
    min-width: 100%;
  }
  
  .tone-pills {
    justify-content: flex-start;
  }
  
  .tone-pill {
    flex: 0 1 auto;
  }
  
  .headline {
    font-size: var(--font-size-xl);
  }
}

@media (max-width: 480px) {
  .header {
    margin-bottom: var(--space-lg);
  }
  
  .headline {
    font-size: var(--font-size-lg);
  }
  
  .subtitle {
    font-size: var(--font-size-sm);
  }
  
  .textarea {
    min-height: 160px;
    padding: var(--space-sm);
  }
}

/* ============================================
   Accessibility - Reduced Motion
   ============================================ */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .background::before {
    animation: none;
  }
}

/* ============================================
   Focus States (Accessibility)
   ============================================ */

*:focus-visible {
  outline: 2px solid rgba(59, 130, 246, 0.5);
  outline-offset: 2px;
}