:root {
  --bg-deep: #0d1b2a;
  --bg-mid: #12263a;
  --panel: rgba(244, 247, 251, 0.93);
  --panel-strong: #ffffff;
  --line: rgba(19, 46, 77, 0.12);
  --text: #102235;
  --muted: #587089;
  --accent: #0f7b6c;
  --accent-deep: #095448;
  --warning: #c67c1f;
  --danger: #b64343;
  --shadow: 0 28px 72px rgba(8, 27, 51, 0.24);
  --radius-lg: 28px;
  --radius-md: 20px;
  --radius-sm: 14px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(62, 193, 167, 0.24), transparent 28%),
    radial-gradient(circle at bottom right, rgba(53, 113, 173, 0.2), transparent 34%),
    linear-gradient(135deg, var(--bg-deep) 0%, var(--bg-mid) 48%, #18334d 100%);
}

button,
select,
textarea {
  font: inherit;
}

.app-shell {
  display: grid;
  grid-template-columns: minmax(280px, 360px) minmax(0, 1fr) minmax(320px, 420px);
  gap: 24px;
  padding: 24px;
  min-height: 100vh;
  align-items: stretch;
}

.panel {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}

.input-panel,
.code-panel,
.preview-panel {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.panel-header h1,
.panel-header h2 {
  margin: 0;
  font-family: "Space Grotesk", "Avenir Next", sans-serif;
  font-weight: 700;
}

.panel-header h1 {
  font-size: clamp(2rem, 4vw, 2.9rem);
  line-height: 0.95;
  margin-top: 8px;
}

.panel-header h2 {
  font-size: 1.45rem;
}

.eyebrow {
  margin: 0;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.72rem;
  font-weight: 700;
}

.intro,
.preview-meta,
.validation-message {
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.group-label {
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

select,
textarea {
  width: 100%;
  appearance: none;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--panel-strong);
  padding: 14px 16px;
  color: var(--text);
}

textarea {
  min-height: 160px;
  resize: vertical;
  font-family: "IBM Plex Mono", "SFMono-Regular", monospace;
  line-height: 1.5;
}

#code-editor {
  min-height: 520px;
}

.example-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.example-chip {
  border: 1px solid rgba(15, 123, 108, 0.2);
  border-radius: 999px;
  background: rgba(15, 123, 108, 0.08);
  color: var(--text);
  padding: 10px 14px;
  cursor: pointer;
}

.summary-list {
  min-height: 120px;
  border-radius: var(--radius-md);
  padding: 14px 16px;
  background: rgba(15, 40, 67, 0.05);
  border: 1px solid rgba(19, 46, 77, 0.08);
  line-height: 1.5;
  color: var(--muted);
}

.hidden {
  display: none;
}

.primary-button {
  border: 0;
  border-radius: 999px;
  padding: 14px 18px;
  background: linear-gradient(135deg, var(--accent), var(--accent-deep));
  color: white;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 20px 40px rgba(15, 123, 108, 0.24);
}

.primary-button:hover,
.secondary-button:hover,
.example-chip:hover {
  filter: brightness(1.03);
}

.secondary-button {
  border: 1px solid rgba(15, 123, 108, 0.22);
  border-radius: 999px;
  padding: 13px 18px;
  background: rgba(255, 255, 255, 0.75);
  color: var(--text);
  cursor: pointer;
}

.action-row {
  display: flex;
  gap: 12px;
}

.action-row-wrap {
  flex-wrap: wrap;
}

.preview-panel {
  min-height: 0;
}

.preview-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: end;
  padding-bottom: 4px;
}

.preview-stage {
  position: relative;
  flex: 1;
  min-height: 560px;
  border-radius: calc(var(--radius-lg) - 8px);
  overflow: hidden;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(235, 242, 248, 0.92));
  border: 1px solid rgba(41, 37, 36, 0.08);
  display: flex;
  align-items: stretch;
  justify-content: stretch;
}

.preview-frame {
  width: 100%;
  height: 100%;
  padding: 24px;
  overflow: auto;
}

.preview-frame svg,
.preview-frame img {
  display: block;
  max-width: 100%;
  margin: 0 auto;
}

.preview-empty {
  position: absolute;
  inset: 24px;
  border-radius: var(--radius-md);
  border: 1px dashed rgba(19, 46, 77, 0.18);
  display: grid;
  place-items: center;
  text-align: center;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.35);
}

.status-row {
  display: flex;
  gap: 14px;
  align-items: center;
}

.status-badge {
  flex: 0 0 auto;
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.status-idle {
  background: rgba(15, 123, 108, 0.1);
  color: var(--accent-deep);
}

.status-valid {
  background: rgba(15, 123, 108, 0.16);
  color: var(--accent-deep);
}

.status-warning {
  background: rgba(198, 124, 31, 0.12);
  color: var(--warning);
}

.status-error {
  background: rgba(182, 67, 67, 0.12);
  color: var(--danger);
}

.info-card {
  margin-top: auto;
}

@media (max-width: 1180px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .preview-stage {
    min-height: 55vh;
  }
}

@media (max-width: 640px) {
  .app-shell {
    padding: 14px;
    gap: 14px;
  }

  .preview-header,
  .status-row {
    flex-direction: column;
    align-items: flex-start;
  }

  .action-row {
    width: 100%;
  }

  .action-row button {
    flex: 1 1 auto;
  }
}