html, body, main, header, footer {
  padding: 0px;
  margin: 0px;
}

/* Material 3 Purple Theme */
:root {
  --md-primary: #6750A4;
  --md-primary-container: #EADDFF;
  --md-on-primary-container: #21005D;
  --md-surface: #FFFBFE;
  --md-surface-container-high: #ECE6F0;
  --md-outline: #79747E;
  --md-outline-variant: #CAC4D0;
  --md-error: #B3261E;
  --md-error-container: #F9DEDC;
  --md-on-error-container: #410E0B;
  --md-on-surface: #1C1B1F;
  --md-on-surface-variant: #49454F;
  --md-radius: 12px;
  --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
  --card-shadow-hover: 0 4px 12px rgba(103, 80, 164, 0.12), 0 2px 4px rgba(0, 0, 0, 0.08);
}

body {
  font-family: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--md-surface);
  color: var(--md-on-surface);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

main {
  max-width: 640px;
  margin: 0 auto;
  padding: 16px;
}

header {
  display: flex;
  justify-content: center;
  padding: 12px 16px;
}

footer {
  text-align: center;
  padding: 24px 16px 32px;
  color: var(--md-on-surface-variant);
  font-size: 13px;
}

footer a {
  color: var(--md-primary);
  text-decoration: none;
}

/* Card */
.card {
  background: #FFFFFF;
  border-radius: var(--md-radius);
  box-shadow: var(--card-shadow);
  margin-bottom: 16px;
  overflow: hidden;
  transition: box-shadow 0.2s ease;
}

.card-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px 20px 0;
}

.card-emoji {
  font-size: 24px;
  line-height: 1;
}

.card-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--md-on-surface);
  margin: 0;
}

.card-body {
  padding: 16px 20px 20px;
}

/* Outlined Text Field */
.outlined-field {
  position: relative;
  display: flex;
  align-items: center;
  border: 1.5px solid var(--md-outline-variant);
  border-radius: 8px 8px 8px 8px;
  background: transparent;
  transition: border-color 0.2s ease;
  flex: 1;
  min-width: 0;
  overflow: hidden;
}

.outlined-field:focus-within {
  border-color: var(--md-primary);
  border-width: 2px;
}

.outlined-field input {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  font-size: 16px;
  color: var(--md-on-surface);
  padding: 12px 0 12px 14px;
  min-width: 0;
  font-family: inherit;
}

.outlined-field input::placeholder {
  color: #999;
}

.field-suffix {
  display: flex;
  align-items: center;
  padding: 0 14px;
  font-size: 14px;
  color: var(--md-on-surface-variant);
  white-space: nowrap;
  border-left: 1px solid var(--md-outline-variant);
  height: 32px;
  line-height: 32px;
}

/* Input Group */
.input-group {
  display: flex;
  gap: 10px;
  align-items: flex-start;
}

.input-row {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  flex-wrap: wrap;
}

.input-row .outlined-field {
  flex: 1;
  min-width: 100px;
}

/* Button */
.btn-convert {
  flex-shrink: 0;
  height: 46px;
  padding: 0 20px;
  border: none;
  border-radius: 24px;
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  font-family: inherit;
  touch-action: manipulation;
  min-width: 44px;
  min-height: 44px;
  white-space: nowrap;
}

.btn-convert:hover {
  background: #D0BCFF;
  box-shadow: 0 1px 3px rgba(103, 80, 164, 0.3);
}

.btn-convert:active {
  transform: scale(0.95);
}

.btn-convert.pulse {
  animation: btnPulse 0.5s ease;
}

@keyframes btnPulse {
  0% { transform: scale(1); background: var(--md-primary); color: #fff; }
  50% { transform: scale(1.08); }
  100% { transform: scale(1); background: var(--md-primary-container); color: var(--md-on-primary-container); }
}

/* Segmented Button */
.segmented-group {
  display: inline-flex;
  border: 1.5px solid var(--md-outline-variant);
  border-radius: 24px;
  overflow: hidden;
  margin-bottom: 14px;
}

.seg-btn {
  padding: 8px 16px;
  border: none;
  background: transparent;
  font-size: 13px;
  font-weight: 500;
  color: var(--md-on-surface-variant);
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  font-family: inherit;
  touch-action: manipulation;
  white-space: nowrap;
  min-height: 36px;
}

.seg-btn:not(:last-child) {
  border-right: 1px solid var(--md-outline-variant);
}

.seg-btn.active {
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  font-weight: 600;
}

.seg-btn:hover:not(.active) {
  background: rgba(103, 80, 164, 0.06);
}

/* Helper Text */
.helper-text {
  font-size: 12px;
  color: var(--md-error);
  min-height: 18px;
  margin-top: 4px;
  padding-left: 4px;
  opacity: 0;
  transition: opacity 0.2s;
}

.helper-text.visible {
  opacity: 1;
}

/* Result Area */
.result-area {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 8px;
  padding: 14px 16px;
  border-radius: 10px;
  background: var(--md-surface-container-high);
  min-height: 48px;
  transition: background 0.3s, transform 0.15s;
}

.result-area.highlight {
  animation: resultHighlight 0.6s ease;
}

.result-area.error-state {
  background: var(--md-error-container);
}

.result-placeholder {
  color: #999;
  font-size: 14px;
  font-style: italic;
}

.result-value {
  font-size: 22px;
  font-weight: 700;
  color: var(--md-primary);
  flex: 1;
  min-width: 0;
  word-break: break-all;
}

.result-value.error-text {
  color: var(--md-error);
  font-size: 14px;
  font-weight: 500;
}

.result-icon {
  font-size: 20px;
  flex-shrink: 0;
}

/* Copy Button */
.btn-copy {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border: 1.5px solid var(--md-outline-variant);
  border-radius: 8px;
  background: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  color: var(--md-on-surface-variant);
  transition: all 0.2s;
  touch-action: manipulation;
}

.btn-copy:hover {
  border-color: var(--md-primary);
  color: var(--md-primary);
}

.btn-copy.copied {
  border-color: #4CAF50;
  color: #4CAF50;
  background: #E8F5E9;
}

/* Content Sections */
#__fork {
  text-align: center;
  padding: 20px 0 8px;
}

#__fork button {
  padding: 10px 28px;
  border: 1.5px solid var(--md-outline-variant);
  border-radius: 24px;
  background: #fff;
  color: var(--md-primary);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
  touch-action: manipulation;
}

#__fork button:hover {
  background: var(--md-primary-container);
  border-color: var(--md-primary);
}

#features, #scenarios, #FAQ {
  background: #FFFFFF;
  border-radius: var(--md-radius);
  box-shadow: var(--card-shadow);
  padding: 20px;
  margin-bottom: 16px;
}

#features h2, #scenarios h2, #FAQ h2 {
  font-size: 18px;
  font-weight: 600;
  color: var(--md-on-surface);
  margin: 0 0 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

#features p {
  font-size: 14px;
  line-height: 1.7;
  color: var(--md-on-surface-variant);
  margin: 0;
}

#scenarios ul {
  margin: 0;
  padding-left: 20px;
}

#scenarios li {
  font-size: 14px;
  line-height: 1.8;
  color: var(--md-on-surface-variant);
}

#FAQ dl {
  margin: 0;
}

#FAQ dt {
  font-size: 15px;
  font-weight: 600;
  color: var(--md-on-surface);
  margin-top: 14px;
  margin-bottom: 4px;
}

#FAQ dt:first-child {
  margin-top: 0;
}

#FAQ dd {
  font-size: 14px;
  line-height: 1.7;
  color: var(--md-on-surface-variant);
  margin: 0 0 8px;
}

@keyframes resultHighlight {
  0% { transform: scale(1); background: var(--md-primary-container); }
  30% { transform: scale(1.03); background: var(--md-primary-container); }
  100% { transform: scale(1); background: var(--md-surface-container-high); }
}

/* Responsive */
@media (max-width: 480px) {
  main {
    padding: 12px;
  }

  .card-header {
    padding: 14px 16px 0;
  }

  .card-body {
    padding: 12px 16px 16px;
  }

  .card-title {
    font-size: 16px;
  }

  .input-row {
    flex-direction: column;
    gap: 8px;
  }

  .input-row .outlined-field {
    min-width: 100%;
  }

  .input-row .btn-convert {
    width: 100%;
  }

  .btn-convert {
    height: 48px;
    font-size: 15px;
  }

  .outlined-field input {
    font-size: 16px;
    padding: 14px 0 14px 14px;
  }

  .seg-btn {
    font-size: 12px;
    padding: 8px 12px;
  }

  .result-value {
    font-size: 20px;
  }

  #features, #scenarios, #FAQ {
    padding: 16px;
  }
}