/* ==========================================================================
   GPT68 · Layout
   布局原语:.shell .section .section-head 等容器与排版基础,
   外加全局存在的几个层:背景渐变、顶部公告、桌面端顶栏。
   ========================================================================== */

/* ---------- 3. Background gradient ---------- */
.bg-deco {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

/* Apple iOS 风格背景渐变 — 5 个饱和色 blob 互相融合 */
.bg-mesh {
  position: absolute;
  inset: -10%;
  background:
    radial-gradient(circle 60vw at 12% 8%,  var(--grad-pink)     0%, transparent 45%),
    radial-gradient(circle 55vw at 88% 18%, var(--grad-blue)     0%, transparent 45%),
    radial-gradient(circle 65vw at 18% 75%, var(--grad-lavender) 0%, transparent 50%),
    radial-gradient(circle 55vw at 92% 78%, var(--grad-peach)    0%, transparent 45%),
    radial-gradient(circle 50vw at 50% 50%, var(--grad-cyan)     0%, transparent 55%),
    var(--bg-base);
  opacity: 1;
  filter: saturate(0.88);
  animation: meshDrift 32s ease-in-out infinite alternate;
}

/* 在网页内容区放一层"奶白磨砂"让色块更柔，但保留色彩饱和度 */
.bg-deco::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(255,255,255,0.42) 0%, rgba(255,255,255,0.28) 50%, rgba(255,255,255,0.42) 100%);
  pointer-events: none;
}

@keyframes meshDrift {
  0%   { transform: translate(0, 0)        scale(1); }
  50%  { transform: translate(2%, -1.5%)   scale(1.03); }
  100% { transform: translate(-2%, 1.5%)   scale(1.06); }
}

@media (prefers-reduced-motion: reduce) {
  .bg-mesh { animation: none; }
}

/* ---------- 4. Layout primitives ---------- */
.shell {
  width: min(var(--shell), calc(100% - 48px));
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

main { position: relative; z-index: 1; }

.section { padding: 96px 0; position: relative; }

.section-head {
  max-width: 720px;
  margin: 0 0 56px;
}

/* 黑色圆角小方块装数字 — 加上微妙渐变和侧边连接线 */
.section-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 11px;
  background: linear-gradient(135deg, var(--ink-1) 0%, #1E293B 100%);
  color: #fff;
  font-weight: 800;
  font-size: 0.92rem;
  letter-spacing: 0.02em;
  margin-bottom: 18px;
  box-shadow:
    0 8px 20px -4px rgba(15, 23, 42, 0.35),
    inset 0 1px 0 rgba(255, 255, 255, 0.12);
  position: relative;
}

/* editorial 排版：数字方块旁边的英文小标签 + 一条短连接线 */
.section-num::after {
  content: attr(data-label);
  position: absolute;
  left: calc(100% + 14px);
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.22em;
  color: var(--ink-2);
  white-space: nowrap;
  text-transform: uppercase;
  padding-left: 24px;
  border-left: 1px solid var(--line-3);
}

.section-num::before {
  content: "";
  position: absolute;
  left: calc(100% + 14px);
  top: 50%;
  width: 16px;
  height: 1px;
  background: var(--line-3);
  z-index: 1;
}

/* 各板块对应的英文小标签（不改 HTML 文案，用属性选择器注入） */
#plans   .section-num::after { content: "PRICING"; }
#reviews .section-num::after { content: "SOCIAL PROOF"; }
#flow    .section-num::after { content: "PROCESS"; }
#trust   .section-num::after { content: "TRUST & SAFETY"; }
#faq     .section-num::after { content: "FAQ"; }
#contact .section-num::after { content: "GET IN TOUCH"; }

/* 移动端把英文小标签隐掉，避免折行 */
@media (max-width: 480px) {
  .section-num::after,
  .section-num::before { display: none; }
}

.section-title {
  font-size: clamp(1.9rem, 3.6vw, 2.7rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.15;
  color: var(--ink-1);
  margin-bottom: 12px;
}

.section-sub {
  font-size: 1rem;
  color: var(--ink-3);
  line-height: 1.65;
  max-width: 560px;
}

/* ---------- 5. Top note ---------- */
.topnote {
  position: relative;
  z-index: 10;
  background: rgba(255, 255, 255, 0.72);
  border-bottom: 1px solid var(--line-1);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.topnote-inner {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 10px 0;
  font-size: 0.85rem;
}

.topnote-dot {
  flex-shrink: 0;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: #10B981;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.18);
  animation: pulseDot 2s ease-in-out infinite;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.topnote-label {
  flex-shrink: 0;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: #10B981;
  padding: 2px 8px;
  border: 1px solid rgba(16, 185, 129, 0.3);
  border-radius: var(--radius-sm);
  background: rgba(16, 185, 129, 0.06);
}

.topnote p {
  color: var(--ink-2);
  font-size: 0.86rem;
  line-height: 1.55;
  margin: 0;
}

/* ---------- 6. Topbar ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.55);
  backdrop-filter: blur(14px) saturate(180%);
  -webkit-backdrop-filter: blur(14px) saturate(180%);
  border-bottom: 1px solid transparent;
  transition:
    background 320ms ease,
    border-color 320ms ease,
    box-shadow 320ms ease,
    backdrop-filter 320ms ease;
}

/* 滚动到 hero 之外时，topbar 变得更"实"，加一点蓝色微光 */
.topbar.is-scrolled {
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom-color: rgba(15, 23, 42, 0.06);
  box-shadow:
    0 8px 28px -10px rgba(15, 23, 42, 0.10),
    0 1px 0 rgba(255, 255, 255, 0.5) inset,
    0 0 0 1px rgba(255, 255, 255, 0.4) inset;
}

.topbar.is-scrolled .topbar-inner {
  height: 60px;
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  transition: height 320ms cubic-bezier(0.22, 1, 0.36, 1);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  transition: opacity 200ms ease;
}

.brand:hover { opacity: 0.7; }

.brand-mark {
  width: 30px; height: 30px;
  display: inline-flex;
  color: var(--blue-600);
}

.brand-name {
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: -0.015em;
  color: var(--ink-1);
}

.brand-name em {
  font-style: normal;
  background: linear-gradient(90deg, #3B82F6 0%, #8B5CF6 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  font-weight: 900;
  padding: 0 1px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 2px;
  position: relative;
}

/* 当前激活项的"滑动指示器"小药丸 */
.nav-indicator {
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 0;
  height: 32px;
  border-radius: 999px;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.10), rgba(139, 92, 246, 0.10));
  border: 1px solid rgba(59, 130, 246, 0.18);
  opacity: 0;
  pointer-events: none;
  transition:
    transform 380ms cubic-bezier(0.22, 1, 0.36, 1),
    width 380ms cubic-bezier(0.22, 1, 0.36, 1),
    opacity 240ms ease;
  z-index: 0;
}

.nav-indicator.is-visible { opacity: 1; }

.nav > a {
  position: relative;
  z-index: 1;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--ink-3);
  padding: 8px 14px;
  border-radius: 999px;
  transition: color 220ms ease, background 220ms ease, transform 220ms ease;
}

.nav > a:hover { color: var(--ink-1); transform: translateY(-1px); }
.nav > a.is-active { color: var(--blue-700); font-weight: 600; }

/* 顶部滚动进度条 */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: transparent;
  z-index: 100;
  pointer-events: none;
}

.scroll-progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg,
    var(--blue-500) 0%,
    #8B5CF6 50%,
    #EC4899 100%);
  box-shadow: 0 1px 6px rgba(59, 130, 246, 0.5);
  transition: width 80ms linear;
  border-top-right-radius: 2px;
  border-bottom-right-radius: 2px;
}

/* 联系客服按钮 — 黑底白字，跟整体黑药丸体系一致 */
.nav-cta {
  margin-left: 10px !important;
  font-weight: 700 !important;
  padding: 8px 18px !important;
  background: linear-gradient(135deg, var(--ink-1) 0%, #1E293B 100%) !important;
  color: #fff !important;
  box-shadow:
    0 6px 16px -3px rgba(15, 23, 42, 0.30),
    0 0 0 1.5px rgba(255, 255, 255, 0.7),
    inset 0 1px 0 rgba(255, 255, 255, 0.10) !important;
}

.nav-cta:hover {
  transform: translateY(-1px);
  background: linear-gradient(135deg, #1E293B 0%, #334155 100%) !important;
  box-shadow:
    0 10px 22px -4px rgba(15, 23, 42, 0.40),
    0 0 0 1.5px rgba(255, 255, 255, 0.85),
    inset 0 1px 0 rgba(255, 255, 255, 0.15) !important;
}

.nav-cta svg {
  width: 14px;
  height: 14px;
}