:root {
  --bg: #eef3f6;
  --panel-bg: #f9fbfd;
  --ink: #0f2230;
  --muted: #4b6778;
  --accent: #117a65;
  --accent-strong: #0c5a4a;
  --danger: #a52222;
  --edge: #d4e0e8;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Trebuchet MS", "Segoe UI", sans-serif;
  color: var(--ink);
  background: radial-gradient(circle at 20% 10%, #ffffff 0, var(--bg) 40%, #dfe9ef 100%);
  overflow-y: auto;
}

.topbar {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--edge);
  background: linear-gradient(135deg, #ffffff 0%, #edf4f8 100%);
}

.topbar h1 {
  margin: 0;
  font-size: 1.35rem;
}

.topbar p {
  margin: 0.35rem 0 0;
  color: var(--muted);
}

.layout {
  display: grid;
  grid-template-columns: minmax(320px, 380px) 1fr;
  gap: 0.85rem;
  padding: 0.85rem;
}

.panel {
  background: var(--panel-bg);
  border: 1px solid var(--edge);
  border-radius: 12px;
  padding: 0.9rem;
}

.panel section {
  margin-bottom: 1rem;
  padding-bottom: 0.8rem;
  border-bottom: 1px dashed var(--edge);
}

.panel section:last-of-type {
  border-bottom: 0;
  margin-bottom: 0;
}

h2 {
  margin: 0 0 0.55rem;
  font-size: 1rem;
}

.advanced-group {
  margin-bottom: 1rem;
  border: 1px solid #d6e3eb;
  border-radius: 10px;
  background: #f6fbfd;
  overflow: hidden;
}

.advanced-group summary {
  cursor: pointer;
  padding: 0.62rem 0.72rem;
  color: var(--muted);
  font-weight: 600;
  list-style: none;
  transition: background-color 120ms ease, color 120ms ease;
}

.advanced-group summary::-webkit-details-marker {
  display: none;
}

.advanced-group summary::before {
  content: "▸";
  display: inline-block;
  margin-right: 0.45rem;
  color: #6f8796;
  transform: translateY(-0.02rem);
  transition: transform 120ms ease;
}

.advanced-group[open] summary::before {
  transform: rotate(90deg) translateX(0.03rem);
}

.advanced-group[open] summary {
  color: #355569;
  background: #eef5f9;
  border-bottom: 1px solid #d9e6ee;
}

.advanced-group summary:hover {
  background: #edf5fa;
}

.advanced-group section {
  margin: 0;
  border-bottom: 0;
  padding: 0.45rem 0.72rem 0.72rem;
}

.advanced-group .adv-block {
  padding: 0.5rem 0 0.1rem;
  border-top: 1px solid #e6eff5;
}

.advanced-group .adv-block:first-child {
  border-top: 0;
  padding-top: 0.15rem;
}

.adv-subtitle {
  margin: 0 0 0.45rem;
  color: #567183;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.advanced-group label {
  margin-bottom: 0.45rem;
  font-size: 0.9rem;
  line-height: 1.3;
}

.advanced-group .inline-check {
  gap: 0.5rem;
  margin-bottom: 0.4rem;
}

.advanced-group .inline-check input[type="checkbox"] {
  margin: 0;
}

.advanced-group input[type="checkbox"]:disabled {
  opacity: 0.65;
}

.advanced-group .inline-check:has(input[type="checkbox"]:disabled) {
  color: #8ea3b1;
}

.advanced-group .derived {
  margin-top: 0.32rem;
  margin-bottom: 0.12rem;
  background: #edf5fa;
  border-color: #d1e0ea;
}

.advanced-group input[type="number"] {
  width: 120px;
}

.face-editor {
  margin-top: 0.35rem;
  padding-top: 0.35rem;
  border-top: 1px dashed #d9e6ee;
}

.face-editor:first-of-type {
  border-top: 0;
  padding-top: 0;
}

.field-hint {
  display: block;
  margin: -0.2rem 0 0.4rem;
  color: #2d5f78;
  font-size: 0.8rem;
}

label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.65rem;
  margin-bottom: 0.5rem;
  color: var(--muted);
  font-size: 0.92rem;
}

.derived {
  margin-top: 0.35rem;
  padding: 0.45rem 0.55rem;
  border-radius: 8px;
  background: #eaf3f8;
  border: 1px solid #c8dae6;
  color: var(--muted);
  font-size: 0.9rem;
}

#inner-summary {
  display: grid;
  grid-template-columns: max-content 1fr;
  column-gap: 0.35rem;
  row-gap: 0.22rem;
  align-items: baseline;
}

#inner-summary .summary-label {
  white-space: nowrap;
}

input,
select,
button {
  font: inherit;
}

input[type="number"],
input[type="text"],
select {
  width: 115px;
  border: 1px solid #b7cad6;
  border-radius: 8px;
  padding: 0.35rem 0.45rem;
  color: var(--ink);
  background: #fff;
}

input[type="text"] {
  width: 100%;
}

.inline-check {
  justify-content: flex-start;
  gap: 0.45rem;
}

button {
  border: 0;
  border-radius: 8px;
  padding: 0.45rem 0.65rem;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
}

button:hover {
  background: var(--accent-strong);
}

.preset-row,
.button-row {
  display: flex;
  gap: 0.45rem;
  margin-bottom: 0.5rem;
}

.primary-row {
  margin-bottom: 0.5rem;
}

.primary-row button {
  width: 100%;
  font-weight: 700;
}

#preset-select {
  width: 100%;
}

#status {
  color: var(--muted);
  font-size: 0.9rem;
}

#errors {
  margin: 0.45rem 0 0;
  padding-left: 1rem;
  font-size: 0.88rem;
}

#errors li.error {
  color: var(--danger);
}

#errors li.info {
  color: #2d5f78;
}

.viewer-wrap {
  position: relative;
  border: 1px solid var(--edge);
  border-radius: 12px;
  background: linear-gradient(180deg, #f5fbff, #eaf1f6);
  min-height: 420px;
}

#viewer {
  width: 100%;
  height: 100%;
  min-height: 420px;
  border-radius: 12px;
}

#viewer-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 0.4rem;
  background: rgba(255, 255, 255, 0.76);
  color: #5f1f1f;
  text-align: center;
  padding: 1rem;
  pointer-events: none;
}

#viewer-overlay[hidden] {
  display: none;
}

#viewer-overlay strong {
  font-size: 1.05rem;
}

@media (max-width: 980px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .panel {
    max-height: none;
  }

  #viewer {
    min-height: 360px;
  }
}