:root {
  font-family: "Segoe UI", Arial, sans-serif;
  --mobile-preview-height: clamp(260px, 45vh, 520px);
}
* { box-sizing: border-box; }

/* ===== Header ===== */
body { margin: 0; background: #f3f5f7; color: #111; }
header {
  position: relative;
  overflow: hidden;
  padding: 10px 18px;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  background:
    radial-gradient(1100px 220px at -8% -120%, rgba(255,255,255,.28), transparent 55%),
    radial-gradient(680px 180px at 92% -95%, rgba(147,197,253,.35), transparent 58%),
    linear-gradient(92deg, #111827 0%, #1e293b 42%, #1f3a63 100%);
  box-shadow: 0 6px 20px rgba(15, 23, 42, .28);
}
header::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, #60a5fa 0%, #c084fc 50%, #22d3ee 100%);
  opacity: .95;
}
header h1 {
  margin: 0;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: .3px;
  text-shadow: 0 1px 0 rgba(0,0,0,.2), 0 0 12px rgba(96,165,250,.35);
}
header p {
  margin: 0;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .45px;
  text-transform: uppercase;
  opacity: .95;
  color: #dbeafe;
  padding: 2px 8px;
  border: 1px solid rgba(191, 219, 254, .35);
  border-radius: 999px;
  background: rgba(30, 41, 59, .42);
  backdrop-filter: blur(2px);
}
.lang-switch {
  margin-left: auto;
  z-index: 1;
}
.lang-switch a {
  display: inline-block;
  color: #eaf2ff;
  text-decoration: none;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .25px;
  padding: 5px 10px;
  border-radius: 999px;
  border: 1px solid rgba(191, 219, 254, .45);
  background: rgba(30, 41, 59, .5);
}
.lang-switch a:hover {
  color: #fff;
  border-color: rgba(147, 197, 253, .8);
  background: rgba(37, 99, 235, .35);
}

/* ===== Mobile layout (default) ===== */
/* Sidebar scrolls, preview fixed at bottom */
.layout {
  display: flex;
  flex-direction: column;
}
.sidebar {
  padding: 10px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-bottom: calc(var(--mobile-preview-height) + 14px); /* clearance for fixed preview */
}
.preview-area {
  position: fixed;
  bottom: 0; left: 0; right: 0;
  height: var(--mobile-preview-height);
  background: #fff;
  border-top: 2px solid #1f2937;
  box-shadow: 0 -4px 20px rgba(0,0,0,.18);
  z-index: 100;
  display: flex;
  flex-direction: column;
  padding: 8px 10px;
  gap: 6px;
}

/* ===== Desktop layout (>= 900px) ===== */
@media (min-width: 900px) {
  html { height: 100%; }
  body {
    height: 100%;
    overflow: hidden;
    display: flex;
    flex-direction: column;
  }
  .layout {
    flex: 1;
    flex-direction: row;
    overflow: hidden;
    min-height: 0;
  }
  header {
    padding: 16px 28px;
    gap: 14px;
    box-shadow: 0 10px 26px rgba(15, 23, 42, .34);
  }
  header h1 {
    font-size: 24px;
    letter-spacing: .45px;
    text-shadow: 0 1px 0 rgba(0,0,0,.25), 0 0 16px rgba(96,165,250,.42);
  }
  header p {
    font-size: 12px;
    padding: 4px 11px;
    border-width: 1px;
  }
  .lang-switch a {
    font-size: 13px;
    padding: 6px 12px;
  }
  .sidebar {
    width: 320px;
    flex-shrink: 0;
    overflow-y: auto;
    background: #f3f5f7;
    border-right: 1px solid #d0d5dc;
    padding: 10px;
    padding-bottom: 10px; /* reset mobile clearance */
  }
  .preview-area {
    position: static;
    flex: 1;
    height: auto;
    overflow: hidden;
    border-top: none;
    box-shadow: none;
    background: #f9fafb;
    padding: 14px 16px;
    gap: 10px;
  }
}

/* ===== Panels ===== */
.panel {
  background: #fff;
  border: 1px solid #d6dbe1;
  border-radius: 8px;
  padding: 10px 12px;
}
.panel h2 {
  margin: 0 0 8px;
  font-size: 11px;
  font-weight: 700;
  color: #6b7280;
  text-transform: uppercase;
  letter-spacing: .6px;
}

/* ===== Form elements ===== */
label { display: block; font-size: 12px; color: #374151; margin-bottom: 6px; }
input, select {
  width: 100%;
  padding: 6px 8px;
  font-size: 13px;
  border: 1px solid #d1d5db;
  border-radius: 5px;
  background: #fff;
  color: #111;
}
button {
  padding: 6px 12px;
  font-size: 13px;
  border: 1px solid #d1d5db;
  border-radius: 5px;
  cursor: pointer;
  background: #f9fafb;
  color: #111;
}
button:hover { background: #e5e7eb; }

/* ===== Style panel render button ===== */
.btn-render {
  display: block;
  width: 100%;
  margin-top: 8px;
  background: #1f2937;
  color: #fff;
  border-color: #1f2937;
  font-weight: 600;
}
.btn-render:hover { background: #374151; }

/* ===== Field grid ===== */
.field-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5px;
}
.field-grid-2 {
  grid-template-columns: 1fr 1fr;
}
.field-groups {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.field-group {
  padding-top: 2px;
}
.field-group + .field-group {
  border-top: 1px solid #eef2f6;
  padding-top: 10px;
}
.field-group-title {
  margin: 0 0 6px;
  font-size: 11px;
  font-weight: 700;
  color: #6b7280;
}
.field-wrapper {
  border: 1px solid #e5e7eb;
  border-radius: 6px;
  padding: 5px 7px;
  transition: border .15s, background .15s, opacity .15s;
  background: #fff;
}
.field-wrapper label { margin-bottom: 2px; font-size: 10px; color: #6b7280; }
.field-wrapper input { padding: 3px 6px; font-size: 12px; margin-top: 1px; }
.field-wrapper.field-active {
  border: 2px solid #f97316;
  background: #fff8f1;
}
.field-wrapper.field-inactive { opacity: .28; }

.convert-actions {
  margin-top: 8px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}

.convert-actions button {
  padding: 5px 8px;
  font-size: 12px;
}

/* ===== Data source panel ===== */
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.source-panel details summary {
  cursor: pointer;
  font-size: 12px;
  font-weight: 700;
  color: #374151;
  user-select: none;
}
.source-body {
  margin-top: 10px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
#use-station { width: 100%; }

/* ===== Preview toolbar ===== */
.preview-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
  padding-bottom: 6px;
  border-bottom: 1px solid #e5e9ee;
}
.toolbar-label {
  font-size: 12px;
  color: #6b7280;
  white-space: nowrap;
  flex-shrink: 0;
}
.size-buttons { display: flex; gap: 4px; }
.size-btn {
  padding: 4px 10px;
  font-size: 12px;
  width: auto;
}
.size-btn.active {
  background: #1f2937;
  color: #fff;
  border-color: #1f2937;
}
.btn-download {
  margin-left: auto;
  background: #2563eb;
  color: #fff;
  border-color: #1d4ed8;
  font-weight: 600;
  white-space: nowrap;
  padding: 5px 14px;
  flex-shrink: 0;
}
.btn-download:hover { background: #1d4ed8; }

/* ===== Canvas wrap ===== */
.canvas-wrap {
  flex: 1;
  overflow: auto;
  /* checkerboard shows canvas boundary */
  background:
    repeating-conic-gradient(#e5e7eb 0% 25%, #f9fafb 0% 50%)
    0 0 / 20px 20px;
  border-radius: 6px;
  min-height: 0;
}
#preview {
  display: block;
  /* natural pixel size — JS sets style.width/height per download scale */
}

/* ===== Status bar ===== */
#status {
  flex-shrink: 0;
  font-size: 11px;
  color: #2c4b75;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.3;
}

.usage-warning {
  flex-shrink: 0;
  font-size: 11px;
  line-height: 1.45;
  color: #7c2d12;
  background: #fff7ed;
  border: 1px solid #fed7aa;
  border-radius: 6px;
  padding: 6px 8px;
}