:root {
  --bg-color: #000000;
  --accent-color: #d4f500;
  --accent-glow: rgba(212, 245, 0, 0.45);
  --text-primary: #ffffff;
  --text-muted: rgba(255, 255, 255, 0.6);
  --card-radius: 22px;
}

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

html, body {
  width: 100%;
  min-height: 100%;
  background-color: var(--bg-color);
  color: var(--text-primary);
  font-family: 'Montserrat', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  overflow-x: hidden;
  overscroll-behavior: none;
  -webkit-font-smoothing: antialiased;
}

html.announcement-active,
body.announcement-active {
  overflow: hidden !important;
  height: 100vh !important;
  max-height: 100vh !important;
}

body.announcement-active #scroll-track {
  display: none !important;
}

/* 纯黑深邃背景 */
#app-bg {
  position: fixed;
  inset: 0;
  background: var(--bg-color);
  z-index: 0;
  pointer-events: none;
}

/* 纵向滚动轨道：长行程让触控板双指滑动极其细腻 */
#scroll-track {
  width: 100%;
  height: 320vh;
  position: relative;
  z-index: 1;
  pointer-events: auto;
}

/* 固定视口舞台：100% 居中锁定 */
#sticky-stage {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: 10;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  pointer-events: none;
  overflow: hidden;
}

/* ================= 居中核心舞台与卡片 ================= */
#center-anchor {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 100vw;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  pointer-events: none;
  z-index: 20;
}

/* 首页卡片：初始 100vw × 100vh，下滚时 scale(1.0) -> scale(0.60) */
#hero-card {
  width: 100vw;
  height: 100vh;
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
  transform-origin: center center;
  border-radius: 0px;
  overflow: hidden;
  pointer-events: auto;
  will-change: transform, border-radius, box-shadow;
  box-shadow: 0 0 0 0 rgba(0, 0, 0, 0);
  background: #000000;
}

/* WebGL2 流体揭晓画布 */
#hero-fluid-canvas {
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
}

/* ================= 笔迹书写覆盖层 ================= */
#signature-stage {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  pointer-events: none;
  z-index: 30;
}

#sig-host {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

#sig-host canvas {
  display: block;
  max-width: 90vw;
  max-height: 80vh;
}

/* ================= GCP 风格开屏公告 (Google Cloud Engineering Design) ================= */
.gcp-overlay {
  position: fixed;
  inset: 0;
  z-index: 9999;
  display: flex;
  justify-content: center;
  align-items: center;
  background: rgba(0, 0, 0, 0.65);
  padding: 24px;
  opacity: 1;
  visibility: visible;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.gcp-overlay.fade-out {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.gcp-card {
  max-width: 580px;
  width: 100%;
  background: #202124;
  border: 1px solid #3c4043;
  border-radius: 8px;
  padding: 22px 24px 20px;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.7), 0 1px 3px rgba(0, 0, 0, 0.3);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: #e8eaed;
  animation: gcpEnter 0.2s cubic-bezier(0.0, 0.0, 0.2, 1);
}

@keyframes gcpEnter {
  0% { transform: scale(0.98); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

.gcp-card-header {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 20px;
}

.gcp-icon-box {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: rgba(138, 180, 248, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 2px;
}

.gcp-header-text {
  flex: 1;
  min-width: 0;
}

.gcp-title {
  font-size: 16px;
  font-weight: 500;
  color: #ffffff;
  line-height: 24px;
  letter-spacing: 0.1px;
  margin-bottom: 6px;
}

.gcp-desc {
  font-size: 13px;
  color: #9aa0a6;
  line-height: 20px;
  letter-spacing: 0.2px;
  white-space: pre-line;
  word-break: break-word;
}

.gcp-close-btn {
  flex-shrink: 0;
  background: transparent;
  border: none;
  color: #9aa0a6;
  cursor: pointer;
  padding: 4px;
  margin-top: -4px;
  margin-right: -4px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s ease, color 0.15s ease;
}

.gcp-close-btn:hover {
  background: rgba(255, 255, 255, 0.08);
  color: #e8eaed;
}

.gcp-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-left: 52px;
}

/* Google Cloud 标志性纯净蓝色主按钮 (无霓虹发光) */
.gcp-btn-primary {
  background: #1a73e8;
  color: #ffffff;
  border: 1px solid transparent;
  border-radius: 4px;
  padding: 7px 18px;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.25px;
  cursor: pointer;
  transition: background 0.15s ease, box-shadow 0.15s ease;
  outline: none;
}

.gcp-btn-primary:hover {
  background: #185abc;
}

.gcp-btn-primary:active {
  background: #174ea6;
}

/* GCP 次要链接按钮 */
.gcp-btn-text {
  background: transparent;
  color: #8ab4f8;
  border: none;
  padding: 7px 12px;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.25px;
  cursor: pointer;
  border-radius: 4px;
  display: flex;
  align-items: center;
  transition: background 0.15s ease;
}

.gcp-btn-text:hover {
  background: rgba(138, 180, 248, 0.08);
}