:root {
  --bg: #0f1117;
  --card-bg: #1a1d29;
  --text: #eef0f5;
  --muted: #9aa1b4;
  --accent: #7c5cff;
  --accent-hover: #9679ff;
  --success: #4ade80;
  --error: #f87171;
  --border: #2a2e3f;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.hero {
  text-align: center;
  padding: 3rem 1.5rem 2rem;
}

.hero h1 {
  margin: 0 0 0.5rem;
  font-size: 2.2rem;
}

.subtitle {
  color: var(--muted);
  margin: 0;
}

main {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 1.5rem 3rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
}

.card h2 {
  margin-top: 0;
}

.btn {
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 8px;
  padding: 0.65rem 1.2rem;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease;
}

.btn:hover {
  background: var(--accent-hover);
}

.btn:active {
  transform: scale(0.98);
}

.output {
  margin-top: 0.75rem;
  min-height: 1.2rem;
  color: var(--muted);
}

.output.success {
  color: var(--success);
}

.output.error {
  color: var(--error);
}

/* Collapsible sections */
.collapsible {
  border-bottom: 1px solid var(--border);
}

.collapsible:last-child {
  border-bottom: none;
}

.collapsible-toggle {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1rem;
  font-weight: 600;
  padding: 0.85rem 0;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.chevron {
  display: inline-block;
  transition: transform 0.2s ease;
  font-size: 0.7rem;
  color: var(--accent);
}

.collapsible-toggle[aria-expanded="true"] .chevron {
  transform: rotate(90deg);
}

.collapsible-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.25s ease;
}

.collapsible-content p {
  margin: 0 0 1rem;
  color: var(--muted);
}

/* Form */
form {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

label {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.5rem;
}

input,
select,
textarea {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.75rem;
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
}

input:focus,
select:focus,
textarea:focus {
  outline: none;
  border-color: var(--accent);
}

form .btn {
  margin-top: 0.75rem;
  align-self: flex-start;
}

footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.85rem;
  padding: 1.5rem;
}