* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; background: #1b1d22; color: #e7e9ee; }
#app { display: flex; height: 100vh; }

#panel {
  width: 300px;
  flex-shrink: 0;
  background: #20232a;
  border-right: 1px solid #2e323b;
  padding: 16px;
  overflow-y: auto;
}
.panel-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
#panel h1 { font-size: 18px; margin: 0; }
#helpBtn {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: #383d48;
  color: #e7e9ee;
  border: none;
  font-size: 14px;
  font-weight: bold;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  margin: 0;
}
#helpBtn:hover { background: #4a5060; }
#panel h2 { font-size: 13px; text-transform: uppercase; letter-spacing: 0.05em; color: #9aa3b2; margin: 0 0 8px; }
#panel section { margin-bottom: 20px; padding-bottom: 16px; border-bottom: 1px solid #2e323b; }
#panel label { display: flex; flex-direction: column; gap: 4px; font-size: 12px; color: #c4c9d4; margin-bottom: 8px; }
#panel input, #panel select {
  background: #15171c;
  border: 1px solid #383d48;
  color: #e7e9ee;
  border-radius: 4px;
  padding: 6px 8px;
  font-size: 13px;
}
#panel input[type="color"] { padding: 2px; height: 32px; }
#panel label.checkbox-row { flex-direction: row; align-items: center; gap: 6px; }
#panel label.checkbox-row input[type="checkbox"] { width: auto; flex: none; }
#panel button {
  background: #3a6ff0;
  color: white;
  border: none;
  border-radius: 4px;
  padding: 8px 12px;
  font-size: 13px;
  cursor: pointer;
  margin-right: 6px;
  margin-bottom: 6px;
}
#panel button:hover { background: #2f5cd0; }
#clearBtn, #deleteBtn { background: #c0392b; }
#clearBtn:hover, #deleteBtn:hover { background: #a5311f; }
.hidden { display: none !important; }
.hint { font-size: 11px; color: #8b93a3; line-height: 1.4; }
.status { font-size: 12px; color: #7fd97f; min-height: 16px; }

#viewport { flex: 1; position: relative; }
#viewport canvas { display: block; }

/* ---------- Tabs ---------- */
.tabs { display: flex; flex-wrap: wrap; gap: 4px; margin-bottom: 12px; }
#panel .tab-btn {
  background: #15171c;
  color: #9aa3b2;
  border: 1px solid #383d48;
  border-radius: 4px;
  padding: 6px 9px;
  font-size: 11px;
  cursor: pointer;
  margin: 0;
}
#panel .tab-btn:hover { background: #15171c; color: #e7e9ee; border-color: #4a5060; }
#panel .tab-btn.active { background: #3a6ff0; color: white; border-color: #3a6ff0; }
.tab-panel { margin-bottom: 4px; }

/* ---------- Help modal ---------- */
#helpModal { position: fixed; inset: 0; z-index: 100; }
#helpModalBackdrop { position: absolute; inset: 0; background: rgba(0, 0, 0, 0.6); }
#helpModalContent {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: min(640px, 90vw);
  max-height: 85vh;
  overflow-y: auto;
  background: #20232a;
  border: 1px solid #383d48;
  border-radius: 8px;
  padding: 24px 28px;
}
#helpModalContent h2 { margin-top: 0; font-size: 20px; }
#helpModalContent h3 { font-size: 14px; color: #9aa3b2; text-transform: uppercase; letter-spacing: 0.05em; margin: 20px 0 8px; }
#helpModalContent p, #helpModalContent li { font-size: 13px; line-height: 1.6; color: #c4c9d4; }
#helpModalContent ul { padding-left: 20px; }
#helpCloseBtn {
  position: absolute;
  top: 16px;
  right: 16px;
  background: transparent;
  border: none;
  color: #9aa3b2;
  font-size: 24px;
  line-height: 1;
  cursor: pointer;
  padding: 0;
}
#helpCloseBtn:hover { color: #e7e9ee; }

.help-tabs-wrap { display: flex; gap: 16px; margin-top: 8px; }
.help-tabs {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 130px;
  flex-shrink: 0;
}
.help-tab-btn {
  background: #15171c;
  color: #9aa3b2;
  border: 1px solid #383d48;
  border-radius: 4px;
  padding: 8px 10px;
  font-size: 12px;
  text-align: left;
  cursor: pointer;
}
.help-tab-btn:hover { color: #e7e9ee; border-color: #4a5060; }
.help-tab-btn.active { background: #3a6ff0; color: white; border-color: #3a6ff0; }
.help-tab-content { flex: 1; min-width: 0; }
.help-panel code {
  background: #15171c;
  border: 1px solid #383d48;
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 12px;
}