:root {
  --bg: #0f1419;
  --bg-card: #1a2332;
  --bg-input: #111827;
  --border: #2d3a4f;
  --text: #e8edf4;
  --text-muted: #8b9cb3;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --success: #22c55e;
  --danger: #ef4444;
  --radius: 12px;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.35);
  --font: "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: "Cascadia Code", "Consolas", "Courier New", monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(59, 130, 246, 0.18), transparent),
    var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.page {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}

.header {
  text-align: center;
  margin-bottom: 2rem;
}

.header__badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  background: rgba(59, 130, 246, 0.15);
  color: #93c5fd;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.header h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
}

.header__lead {
  margin: 0 auto;
  max-width: 560px;
  color: var(--text-muted);
}

.layout {
  display: grid;
  gap: 1.25rem;
}

@media (min-width: 900px) {
  .layout {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }

  .card--version,
  .form {
    grid-column: 1;
  }

  .card--preview {
    grid-column: 2;
    grid-row: 1 / span 10;
    position: sticky;
    top: 1.25rem;
  }
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow);
}

.card h2 {
  margin: 0 0 1rem;
  font-size: 1.05rem;
  font-weight: 600;
}

.version-description {
  margin: 0.75rem 0 0;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.form {
  display: grid;
  gap: 1rem;
}

.block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow);
}

.block__title {
  margin: 0 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
  font-weight: 600;
  color: #cbd5e1;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-bottom: 0.9rem;
}

.field:last-child {
  margin-bottom: 0;
}

.field__description {
  font-size: 0.85rem;
  font-weight: 600;
  color: #cbd5e1;
}

.field__description-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.field--checkbox .field__description-row {
  flex: 1;
}

.field__control {
  width: 100%;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-input);
  color: var(--text);
  font: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.field__control:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.field__control--invalid {
  border-color: var(--danger);
}

.field--checkbox {
  flex-direction: row;
  align-items: center;
  gap: 0.6rem;
}

.field--checkbox .field__control {
  width: auto;
  accent-color: var(--accent);
}

.preview-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.preview-header h2 {
  margin: 0;
}

.json-preview {
  margin: 0 0 1rem;
  padding: 1rem;
  min-height: 220px;
  max-height: 420px;
  overflow: auto;
  border-radius: 8px;
  background: #0b1020;
  border: 1px solid var(--border);
  font-family: var(--mono);
  font-size: 0.8rem;
  line-height: 1.45;
  white-space: pre-wrap;
  word-break: break-word;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.65rem 1.1rem;
  border: none;
  border-radius: 8px;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
}

.btn:active {
  transform: translateY(1px);
}

.btn--primary {
  background: var(--accent);
  color: #fff;
}

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

.btn--secondary {
  background: #243044;
  color: var(--text);
  border: 1px solid var(--border);
}

.btn--secondary:hover {
  background: #2d3d56;
}

.btn--ghost {
  padding: 0.4rem 0.75rem;
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
  font-size: 0.85rem;
}

.btn--ghost:hover {
  color: var(--text);
  border-color: #4b607d;
}

.build-hint {
  margin: 0.75rem 0 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer {
  margin-top: 2rem;
  text-align: center;
  font-size: 0.85rem;
}

.footer__links,
.footer__feedback {
  margin: 0;
}

.footer__feedback {
  margin-top: 0.5rem;
  color: var(--text-muted);
}

.footer__thanks {
  display: inline-flex;
  margin-top: 1rem;
  text-decoration: none;
}

.btn--thanks {
  padding: 0.5rem 1rem;
  background: rgba(34, 197, 94, 0.15);
  color: #86efac;
  border: 1px solid rgba(34, 197, 94, 0.35);
  font-size: 0.85rem;
}

.btn--thanks:hover {
  background: rgba(34, 197, 94, 0.25);
  border-color: rgba(34, 197, 94, 0.5);
  text-decoration: none;
}

.footer a {
  color: #93c5fd;
  text-decoration: none;
}

.footer a:hover {
  text-decoration: underline;
}

.btn-help {
  flex-shrink: 0;
  padding: 0.15rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: transparent;
  color: #93c5fd;
  font-size: 0.72rem;
  font-weight: 600;
  cursor: pointer;
}

.btn-help:hover {
  background: rgba(59, 130, 246, 0.12);
  border-color: #4b607d;
}

.preview-header__actions {
  display: flex;
  gap: 0.5rem;
}

.help-dialog {
  width: min(520px, calc(100vw - 2rem));
  padding: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-card);
  color: var(--text);
  box-shadow: var(--shadow);
}

.help-dialog::backdrop {
  background: rgba(0, 0, 0, 0.55);
}

.help-dialog__inner {
  padding: 1.25rem;
}

.help-dialog__title {
  margin: 0 0 1rem;
  font-size: 1.05rem;
}

.help-dialog__content {
  margin-bottom: 1.25rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.help-steps {
  margin: 0;
  padding-left: 1.25rem;
}

.help-steps li {
  margin-bottom: 0.5rem;
}

.help-steps li:last-child {
  margin-bottom: 0;
}

.btn--block {
  width: 100%;
  margin-top: 0.75rem;
}

.import-dialog__hint {
  margin: 0 0 0.75rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.import-dialog__textarea {
  width: 100%;
  margin-bottom: 0.75rem;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #0b1020;
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.8rem;
  line-height: 1.45;
  resize: vertical;
}

.import-dialog__textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.import-dialog__error {
  margin: 0 0 0.75rem;
  font-size: 0.85rem;
  color: var(--danger);
}

.import-dialog__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: flex-end;
}

.import-dialog__actions .btn--ghost {
  margin-right: auto;
}

.help-dialog__close {
  width: 100%;
}

.hidden {
  display: none !important;
}