* {
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background: radial-gradient(circle at top, #020617, #000);
  color: #e5e7eb;
  padding: 40px;
}

h1 {
  text-align: center;
  margin-bottom: 25px;
  letter-spacing: 0.5px;
}

.container {
  max-width: 650px;
  margin: auto;
  background: rgba(2, 6, 23, 0.9);
  padding: 24px;
  border-radius: 14px;
  border: 1px solid #1e293b;
  box-shadow: 0 0 30px rgba(56, 189, 248, 0.05);
  backdrop-filter: blur(8px);
}

label {
  display: block;
  margin-bottom: 18px;
  font-size: 14px;
}

textarea,
input {
  width: 100%;
  margin-top: 6px;
  padding: 10px;
  background: #020617;
  color: #e5e7eb;
  border: 1px solid #334155;
  border-radius: 8px;
  outline: none;
  font-size: 14px;
}

textarea {
  height: 120px;
  resize: vertical;
}

textarea:focus,
input:focus {
  border-color: #38bdf8;
  box-shadow: 0 0 0 1px rgba(56, 189, 248, 0.4);
}

.library-title {
  font-size: 13px;
  opacity: 0.8;
  margin-bottom: 6px;
}

.library {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.library button {
  background: #020617;
  color: #e5e7eb;
  border: 1px solid #334155;
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.library button:hover {
  border-color: #38bdf8;
  box-shadow: 0 0 10px rgba(56, 189, 248, 0.3);
  transform: translateY(-1px);
}

#result {
  margin-top: 10px;
  font-weight: 600;
}

.preview {
  margin-top: 14px;
  padding: 12px;
  background: #020617;
  border: 1px solid #1e293b;
  border-radius: 8px;
  white-space: pre-wrap;
}

mark {
  background: linear-gradient(90deg, #22c55e, #4ade80);
  color: #020617;
  padding: 2px 4px;
  border-radius: 4px;
}

.explanation {
  margin-top: 12px;
  font-size: 13px;
  opacity: 0.85;
  line-height: 1.5;
}

.reset-btn {
  margin-top: 6px;
  margin-bottom: 10px;
  background: transparent;
  color: #94a3b8;
  border: 1px dashed #334155;
  border-radius: 8px;
  padding: 8px;
  cursor: pointer;
  font-size: 13px;
  transition: all 0.2s ease;
}

.reset-btn:hover {
  color: #e5e7eb;
  border-color: #38bdf8;
  box-shadow: 0 0 10px rgba(56, 189, 248, 0.25);
}