:root {
  --bg-deep: #02060c;
  --panel-bg: rgba(8, 16, 28, 0.78);
  --panel-border: rgba(90, 180, 255, 0.22);
  --accent: #59c7ff;
  --accent-strong: #8fdcff;
  --text: #dfeaf3;
  --text-dim: #8fa5b8;
  --danger: #ff7a6b;
  font-size: 15px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg-deep);
  color: var(--text);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", "Segoe UI", system-ui, sans-serif;
}

#app, #scene-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

/* ---------- top bar ---------- */
#topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 16px;
  background: linear-gradient(180deg, rgba(3, 9, 18, 0.86), rgba(3, 9, 18, 0.35) 75%, transparent);
  pointer-events: none;
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand-title {
  font-size: 1.15rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--accent-strong);
  text-shadow: 0 0 12px rgba(89, 199, 255, 0.35);
}

.brand-sub {
  font-size: 0.72rem;
  color: var(--text-dim);
  letter-spacing: 0.04em;
}

#mode-nav {
  display: flex;
  gap: 8px;
  pointer-events: auto;
}

.mode-btn {
  appearance: none;
  border: 1px solid var(--panel-border);
  background: rgba(10, 20, 34, 0.7);
  color: var(--text);
  font-size: 0.85rem;
  padding: 7px 14px;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.18s, border-color 0.18s, color 0.18s;
  font-family: inherit;
}

.mode-btn:hover {
  border-color: var(--accent);
  color: var(--accent-strong);
}

.mode-btn.active {
  background: rgba(24, 86, 138, 0.85);
  border-color: var(--accent);
  color: #fff;
  box-shadow: 0 0 14px rgba(89, 199, 255, 0.35);
}

/* ---------- panels ---------- */
.panel {
  position: fixed;
  top: 68px;
  left: 16px;
  z-index: 15;
  width: 250px;
  max-width: calc(100vw - 32px);
  padding: 12px 14px;
  border-radius: 12px;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.45);
  pointer-events: auto;
}

.panel h3 {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--accent-strong);
  margin-bottom: 8px;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--panel-border);
  padding-bottom: 6px;
}

.panel ul {
  list-style: none;
  display: grid;
  gap: 4px;
}

.panel li {
  font-size: 0.78rem;
  color: var(--text-dim);
  display: flex;
  justify-content: space-between;
  gap: 8px;
}

.panel li::before {
  content: "▪";
  color: var(--accent);
  opacity: 0.8;
  font-size: 0.6rem;
  align-self: center;
}

.panel-note {
  margin-top: 8px;
  font-size: 0.72rem;
  color: var(--accent);
  opacity: 0.85;
}

.hidden {
  display: none !important;
}

#section-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-bottom: 10px;
}

#section-list .mode-btn {
  width: 100%;
  text-align: center;
  padding: 6px 4px;
  font-size: 0.74rem;
  border-radius: 8px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.section-desc {
  font-size: 0.76rem;
  line-height: 1.55;
  color: var(--text-dim);
}

#mode-hint {
  position: fixed;
  bottom: 14px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 14;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: rgba(180, 210, 235, 0.75);
  background: rgba(5, 12, 22, 0.55);
  border: 1px solid rgba(90, 180, 255, 0.16);
  padding: 5px 12px;
  border-radius: 999px;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  white-space: nowrap;
}

/* ---------- labels & tooltip ---------- */
#labels-layer {
  position: fixed;
  inset: 0;
  z-index: 12;
  pointer-events: none;
  overflow: hidden;
}

.ship-label {
  position: absolute;
  transform: translate(-50%, -130%);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--accent-strong);
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.95);
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.25s;
}

.ship-label .lb-dim {
  color: var(--text-dim);
  font-size: 0.62rem;
  margin-left: 4px;
}

#tooltip {
  position: fixed;
  z-index: 25;
  padding: 6px 10px;
  border-radius: 8px;
  background: rgba(8, 18, 30, 0.92);
  border: 1px solid var(--panel-border);
  color: var(--text);
  font-size: 0.76rem;
  pointer-events: none;
  max-width: 240px;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.5);
}

/* ---------- intro & loading ---------- */
#intro-card {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 30;
  width: min(520px, calc(100vw - 40px));
  padding: 26px 28px;
  border-radius: 16px;
  background: rgba(5, 12, 22, 0.9);
  border: 1px solid var(--panel-border);
  box-shadow: 0 16px 60px rgba(0, 0, 0, 0.7);
  text-align: center;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

#intro-card h2 {
  font-size: 1.35rem;
  font-weight: 500;
  color: var(--accent-strong);
  letter-spacing: 0.12em;
  margin-bottom: 14px;
  text-shadow: 0 0 18px rgba(89, 199, 255, 0.4);
}

#intro-card p {
  font-size: 0.85rem;
  line-height: 1.8;
  color: var(--text-dim);
  text-align: left;
}

#intro-card .intro-hint {
  margin-top: 8px;
  font-size: 0.76rem;
  color: var(--accent);
  text-align: center;
}

#intro-card .mode-btn {
  margin-top: 18px;
  font-size: 0.9rem;
  padding: 9px 26px;
}

#loading {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-dim);
  font-size: 0.85rem;
  letter-spacing: 0.08em;
}

.spinner {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid rgba(89, 199, 255, 0.2);
  border-top-color: var(--accent);
  animation: spin 0.9s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

#error-card {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 50;
  width: min(420px, calc(100vw - 40px));
  padding: 22px;
  border-radius: 14px;
  background: rgba(30, 8, 8, 0.92);
  border: 1px solid rgba(255, 122, 107, 0.5);
  text-align: center;
}

#error-card h2 {
  color: var(--danger);
  font-size: 1rem;
  margin-bottom: 8px;
  font-weight: 500;
}

#error-card p {
  font-size: 0.8rem;
  color: var(--text-dim);
  line-height: 1.6;
}

/* ---------- responsive ---------- */
@media (max-width: 720px) {
  #spec-panel {
    width: 212px;
  }

  .brand-sub {
    display: none;
  }

  #section-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  #spec-panel {
    top: auto;
    bottom: 56px;
    left: 8px;
    width: 186px;
    padding: 8px 10px;
  }

  .panel li {
    font-size: 0.7rem;
  }

  .panel h3 {
    font-size: 0.82rem;
  }
}