:root {
  /* Interface Design: Architectural Slate & Obsidian Surface Hierarchy (60/30/10) */
  --surface-canvas: #0a0d14;
  --surface-1: rgba(17, 22, 34, 0.86);
  --surface-2: rgba(25, 32, 48, 0.92);
  --surface-control: rgba(30, 39, 56, 0.65);
  --surface-control-hover: rgba(40, 52, 74, 0.85);

  /* Hairline Border Progression (Whisper-quiet structure) */
  --border-subtle: rgba(255, 255, 255, 0.07);
  --border-strong: rgba(255, 255, 255, 0.14);
  --border-focus: rgba(56, 189, 248, 0.48);
  --specular-top: inset 0 1px 0 rgba(255, 255, 255, 0.06);

  /* Four-Tier Typography Hierarchy */
  --fg-primary: #f8fafc;
  --fg-secondary: #cbd5e1;
  --fg-tertiary: #94a3b8;
  --fg-muted: #64748b;

  /* Intentional Semantic Accents (10% allocation) */
  --accent-primary: #38bdf8;
  --accent-ten: #10b981;
  --accent-warn: #f59e0b;
  --accent-danger: #f43f5e;

  /* Concentric Radii & 4px Base Spacing Scale */
  --radius-outer: 12px;
  --radius-lg: 16px;
  --radius-inner: 8px;
  --radius-xs: 5px;

  /* Emil Kowalski Custom Easing Curves (Never use ease-in) */
  --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
  --ease-in-out: cubic-bezier(0.77, 0, 0.175, 1);
  --ease-drawer: cubic-bezier(0.32, 0.72, 0, 1);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: var(--surface-canvas);
  background-image: radial-gradient(circle at 50% 42%, #131b2e 0%, #0a0d14 75%);
  font-family: -apple-system, BlinkMacSystemFont, "Inter", "SF Pro Display", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--fg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 3-Row Non-Overlapping App Shell (4px/8px grid spacing) */
.app-shell {
  width: 100vw;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  gap: 8px;
}

/* ========================================================
   ROW 1: TOP INSTRUMENT BAR (Zero nested cards)
   ======================================================== */
.hud-top {
  width: 100%;
  max-width: 960px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 10;
}

.instrument-bar {
  /* 中间态: 容器各保一条 hairline, 组件级零边框 */
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 8px 12px 8px 16px;
  border-radius: var(--radius-outer);
  background: var(--surface-1);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-subtle);
}

.brand-lockup {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

/* Distill: 品牌标记去掉盒体, 只留一枚字面字母 *N* */
.brand-mark {
  color: var(--accent-primary);
  font-weight: 800;
  font-size: 22px;
  line-height: 1;
  display: inline-flex;
  align-items: center;
  letter-spacing: -0.04em;
  text-shadow: 0 0 24px rgba(56, 189, 248, 0.35);
}

/* 品牌: 视觉让位给玩法数据 (Data is the hero — brand stays quiet) */
.brand-copy h1 {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--fg-primary);
  line-height: 1.25;
}

.brand-copy p {
  font-size: 10.5px;
  font-weight: 400;
  color: var(--fg-tertiary);
  line-height: 1.3;
}

.v-divider {
  /* Distill: 分割线全部撤除, 用留白分组 */
  display: none;
}

/* Open Typographic Ledger (Replaces nested boxed cards) */
.metrics-ledger {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  flex: 1;
  padding: 0 8px;
}

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

.ledger-label {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
  text-transform: uppercase;
}

.ledger-main {
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.ledger-value {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--fg-primary);
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
  min-width: 2.4ch; /* tabular 网格: 数值宽度不随 0/6 -> 6/12 抖动 */
}

.ledger-value.accent-figure {
  color: var(--accent-primary);
}

.ledger-sub {
  font-size: 11px;
  font-weight: 500;
  color: var(--fg-tertiary);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Utility Controls (Concentric 8px inner radius, 36px height) */
.utility-controls {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.icon-control {
  /* Distill: 默认无底无框, 悬停才亮起操作面 (quieter 原则) */
  height: 34px;
  padding: 0 10px;
  border-radius: var(--radius-inner);
  background: transparent;
  border: none;
  color: var(--fg-tertiary);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: transform 140ms var(--ease-out), background-color 150ms ease, color 150ms ease;
}

@media (hover: hover) and (pointer: fine) {
  .icon-control:hover {
    background: rgba(255, 255, 255, 0.06);
    color: var(--fg-primary);
  }
}

/* 语言开关的字母标签: 加重且在移动端保可见 */
.lang-flag {
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.04em;
}

.icon-control:active {
  transform: scale(0.97);
}

.icon-control:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

/* Telemetry Strip: Signature Area Equation Pill + Status Caption (零压力切分, 无计时器) */
.telemetry-strip {
  /* Distill: 无底无框, 裸排 */
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 6px 12px;
  border-radius: var(--radius-outer);
  background: var(--surface-1);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-subtle);
  min-height: 40px;
}

/* Signature Element (/delight): Live Area Equation Inspector Pill */
/* 算式检视器: 外壳去盒, 仅读数 token 保留微底 */
.equation-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0;
  font-size: 12px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--fg-secondary);
  flex-shrink: 0;
  transition: transform 160ms var(--ease-out), color 160ms ease;
}

.equation-pill.is-active {
  color: var(--fg-primary);
}

.equation-pill.is-matched {
  color: #6ee7b7;
  transform: scale(1.03);
}

.eq-slot {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 20px;
  height: 20px;
  padding: 0 5px;
  border-radius: var(--radius-xs);
  background: rgba(255, 255, 255, 0.07);
  color: var(--fg-primary);
  font-weight: 700;
}

.eq-op, .eq-res {
  color: var(--fg-tertiary);
  font-weight: 500;
}

.status-caption {
  flex: 1;
  font-size: 12px;
  font-weight: 400;
  color: var(--fg-tertiary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: opacity 150ms var(--ease-out), filter 150ms var(--ease-out);
}

.status-caption.blur-swap {
  opacity: 0.65;
  filter: blur(1.5px);
}

/* Drag-invalid: 面积不等 / 覆盖已填区域时的警示态 */
.equation-pill.is-warn {
  color: #fcd34d;
}

/* ========================================================
   ROW 2: DEDICATED CENTER 3D STAGE
   ======================================================== */
.stage-middle {
  position: relative;
  width: 100%;
  flex: 1;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.webgl-container {
  width: 100%;
  height: 100%;
  position: relative;
  cursor: pointer;
}

.webgl-container canvas {
  display: block;
  width: 100% !important;
  height: 100% !important;
}

.fx-overlay {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 12;
  overflow: hidden;
}

/* Emil Kowalski rule: Never animate from scale(0); use scale(0.92) + custom ease-out */
.floating-pop {
  position: absolute;
  transform: translate(-50%, -50%);
  font-weight: 700;
  font-size: 16px;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
  padding: 4px 10px;
  border-radius: var(--radius-inner);
  background: rgba(15, 23, 42, 0.85);
  white-space: nowrap;
  pointer-events: none;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.45);
  animation: popCallout 680ms var(--ease-out) forwards;
}

@keyframes popCallout {
  0% {
    opacity: 0;
    transform: translate(-50%, -20%) scale(0.92);
  }
  22% {
    opacity: 1;
    transform: translate(-50%, -90%) scale(1.04);
  }
  100% {
    opacity: 0;
    transform: translate(-50%, -165%) scale(0.96);
  }
}

/* ========================================================
   ROW 3: BOTTOM TACTICAL COMMAND DOCK
   ======================================================== */
.hud-bottom {
  width: 100%;
  max-width: 720px;
  flex-shrink: 0;
  z-index: 10;
}

.tactical-dock {
  /* 中间态: dock 保一条 hairline, 按钮组件级无边框 */
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  padding: 4px;
  border-radius: var(--radius-outer);
  background: var(--surface-1);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-subtle);
}

.tactical-btn {
  /* Distill: 无底无框, 悬停亮面 */
  height: 44px;
  padding: 0 12px;
  border-radius: var(--radius-inner);
  background: transparent;
  border: none;
  color: var(--fg-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: transform 140ms var(--ease-out), background-color 150ms ease, opacity 150ms ease;
}

@media (hover: hover) and (pointer: fine) {
  .tactical-btn:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.06);
  }
}

.tactical-btn:active:not(:disabled) {
  transform: scale(0.97);
}

.tactical-btn:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

.tactical-btn:disabled {
  opacity: 0.36;
  cursor: not-allowed;
}

.tactical-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-primary);
}

.tactical-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--fg-primary);
  white-space: nowrap;
}

.tactical-kbd {
  /* 仅存的三种表面之一: 数据读数 chip, 无边框 */
  font-family: inherit;
  font-size: 10px;
  font-weight: 600;
  padding: 1px 5px;
  border-radius: var(--radius-xs);
  background: rgba(255, 255, 255, 0.05);
  border: none;
  color: var(--fg-muted);
}

/* 算式检视器 idle 态: 占位符弱化未填充感, 拖拽时才点亮 */
.equation-pill.is-idle .eq-slot,
.equation-pill.is-idle .eq-op,
.equation-pill.is-idle .eq-res {
  opacity: 0.45;
}


/* ========================================================
   MODAL DIALOG (Enters from scale(0.95), under 250ms)
   ======================================================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 50;
  background: rgba(6, 9, 15, 0.76);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 200ms var(--ease-out);
}

.modal-backdrop.show {
  opacity: 1;
  pointer-events: auto;
}

/* Emil: 出场永远快于进场 (220ms in / 160ms out) */
.modal-backdrop.closing {
  opacity: 0;
  pointer-events: none;
  transition: opacity 160ms var(--ease-out);
}

.modal-backdrop.closing .modal-card {
  transform: scale(0.97);
  opacity: 0;
  transition: transform 160ms var(--ease-out), opacity 160ms var(--ease-out);
}

.modal-card {
  width: 100%;
  max-width: 380px;
  background: var(--surface-2);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.6);
  transform: scale(0.95);
  opacity: 0;
  transition: transform 220ms var(--ease-out), opacity 220ms var(--ease-out);
}

.modal-backdrop.show .modal-card {
  transform: scale(1);
  opacity: 1;
}

.modal-backdrop.show.closing .modal-card {
  transform: scale(0.97);
  opacity: 0;
}

.modal-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: var(--radius-xs);
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.28);
  color: var(--accent-primary);
  margin-bottom: 12px;
}

.modal-title {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--fg-primary);
  margin-bottom: 6px;
  text-wrap: balance;
}

.modal-desc {
  font-size: 13px;
  color: var(--fg-tertiary);
  line-height: 1.5;
  margin-bottom: 20px;
  text-wrap: pretty;
}

.modal-ledger {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  padding: 12px 0;
  margin-bottom: 20px;
}

.modal-metric {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.modal-metric:not(:last-child) {
  border-right: 1px solid var(--border-subtle);
}

.modal-metric span {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
}

.modal-metric strong {
  font-size: 18px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--fg-primary);
}

.modal-actions {
  display: flex;
  gap: 8px;
}

.btn-primary,
.btn-secondary {
  flex: 1;
  height: 40px;
  padding: 0 16px;
  border-radius: var(--radius-inner);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 140ms var(--ease-out), background-color 150ms ease, border-color 150ms ease;
}

.btn-primary {
  background: var(--accent-primary);
  color: #06101e;
}

.btn-secondary {
  background: var(--surface-control);
  border: 1px solid var(--border-subtle);
  color: var(--fg-secondary);
}

.btn-primary:active,
.btn-secondary:active {
  transform: scale(0.97);
}

/* Responsive Layout & Reduced Motion Support */
@media (max-width: 760px) {
  .app-shell {
    padding: 8px 10px;
    gap: 6px;
  }
  .instrument-bar {
    flex-wrap: wrap;
    gap: 8px;
    padding: 8px 10px;
  }
  .brand-copy p,
  .v-divider,
  .control-label,
  .tactical-kbd {
    display: none;
  }
  .lang-flag {
    display: inline;
    font-size: 12px;
  }
  .status-caption {
    white-space: normal;
  }
  .metrics-ledger {
    order: 3;
    width: 100%;
    padding: 6px 0 0;
    gap: 8px;
  }
  .ledger-value {
    font-size: 15px;
  }
  .ledger-sub {
    font-size: 10px;
  }

}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}