/* TTB Number ↔ Roman Converter – Modern UI */
.ttb-wrap.ttb-nrc {
  --ttb-bg: #0f1115;
  --ttb-card: #151923;
  --ttb-muted: #9aa4b2;
  --ttb-border: #232838;
  --ttb-text: #e8ecf1;
  --ttb-accent: #2dd4bf;
  --ttb-danger: #ef4444;
  --ttb-radius: 16px;
  --ttb-shadow: 0 6px 24px rgba(0,0,0,.25);
  color: var(--ttb-text);
  background: linear-gradient(180deg, #0c0f14 0%, #0f1115 100%);
  padding: 24px;
  border-radius: var(--ttb-radius);
  box-shadow: var(--ttb-shadow);
}

.ttb-header { margin-bottom: 20px; text-align: center; }
.ttb-title { font-size: 1.6rem; margin: 0 0 6px; }
.ttb-subtitle { margin: 0; color: var(--ttb-muted); font-size: .95rem; }

.ttb-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}
@media (min-width: 860px){
  .ttb-grid { grid-template-columns: 1fr 1fr; }
}

.ttb-card {
  background: var(--ttb-card);
  border: 1px solid var(--ttb-border);
  border-radius: var(--ttb-radius);
  padding: 16px;
}
.ttb-card-title { margin: 0 0 12px; font-size: 1.1rem; }

.ttb-field { display: grid; gap: 8px; margin-bottom: 12px; }
.ttb-field label { color: var(--ttb-muted); font-size: .9rem; }
.ttb-field input[type="text"],
.ttb-field input[type="number"]{
  width: 100%;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid var(--ttb-border);
  background: #0e121b;
  color: var(--ttb-text);
  outline: none;
}
.ttb-field input:focus{ border-color: var(--ttb-accent); box-shadow: 0 0 0 3px rgba(45,212,191,.15); }

.ttb-actions { display: flex; gap: 10px; margin-bottom: 12px; }
.ttb-btn {
  appearance: none;
  border: 1px solid var(--ttb-border);
  background: #0e141a;
  padding: 10px 14px;
  border-radius: 12px;
  cursor: pointer;
  color: var(--ttb-text);
  font-weight: 600;
  transition: transform .08s ease, box-shadow .2s ease, border-color .2s ease;
}
.ttb-btn:hover{ border-color: var(--ttb-accent); box-shadow: 0 4px 14px rgba(45,212,191,.1); transform: translateY(-1px); }
.ttb-btn:active{ transform: translateY(0); }
.ttb-btn-ghost{ background: transparent; }
.ttb-btn-sm{ padding: 6px 10px; font-size: .85rem; }

.ttb-output {
  border: 1px dashed var(--ttb-border);
  border-radius: 12px;
  padding: 12px;
  background: rgba(14, 17, 26, .6);
}
.ttb-output-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 8px; color: var(--ttb-muted); }
.ttb-result { display: block; min-height: 28px; font-size: 1.15rem; letter-spacing: .5px; }

.ttb-error { margin: 8px 0 0; color: var(--ttb-danger); font-size: .9rem; min-height: 1.2em; }

.ttb-footer { margin-top: 10px; color: var(--ttb-muted); font-size: .85rem; text-align: center; }