/* ==========================================================================
   TrollFools 落地页样式
   配色遵循 Apple 浅色视觉：白 / 浅灰底 + 深空灰文字 + iOS 蓝，
   并以 Logo 的蓝紫渐变作为点缀色。
   ========================================================================== */

:root {
  --bg: #fbfbfd;
  --surface: #ffffff;
  --surface-alt: #f5f5f7;
  --ink: #1d1d1f;
  --muted: #6e6e73;
  --faint: #86868b;
  --line: rgba(0, 0, 0, 0.09);
  --line-strong: rgba(0, 0, 0, 0.14);

  --blue: #0071e3;
  --blue-hover: #0077ed;
  --sky: #7cc7f7;
  --violet: #a78bfa;
  --indigo: #6d5dfc;

  --grad: linear-gradient(115deg, #2f9cf6 0%, #5b8dfa 45%, #a78bfa 100%);
  --grad-soft: linear-gradient(140deg, rgba(124, 199, 247, 0.9), rgba(167, 139, 250, 0.9));

  --radius-xs: 12px;
  --radius-sm: 16px;
  --radius-md: 22px;
  --radius-lg: 30px;

  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-sm: 0 6px 18px rgba(16, 24, 40, 0.06);
  --shadow-md: 0 18px 40px rgba(16, 24, 40, 0.1);
  --shadow-lg: 0 30px 70px rgba(16, 24, 40, 0.16);

  --max: 1180px;
  --header-h: 64px;
  --ease: cubic-bezier(0.22, 0.82, 0.2, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro SC",
    "PingFang SC", "Helvetica Neue", "Microsoft YaHei", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  display: block;
}

/* 所有留空的 img（Logo、首屏截图）先透明，填入地址后自动显示 */
img[src=""] {
  opacity: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  color: inherit;
  border: 0;
  background: none;
  cursor: pointer;
}

h1,
h2,
h3 {
  margin: 0;
  font-weight: 700;
  letter-spacing: -0.022em;
  line-height: 1.18;
}

p {
  margin: 0;
}

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

code {
  font-family: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: rgba(0, 113, 227, 0.08);
  color: #0060c0;
  border-radius: 5px;
  padding: 0.1em 0.36em;
}

:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
  border-radius: 6px;
}

.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding-inline: clamp(20px, 5vw, 40px);
}

/* --------------------------------------------------------------------------
   通用组件
   -------------------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 44px;
  padding: 0 22px;
  border-radius: 980px;
  font-size: 15px;
  font-weight: 500;
  line-height: 1;
  white-space: nowrap;
  transition: background-color 0.25s var(--ease), transform 0.25s var(--ease),
    box-shadow 0.25s var(--ease), color 0.25s var(--ease);
}

.btn-primary {
  background: var(--blue);
  color: #fff;
  box-shadow: 0 6px 18px rgba(0, 113, 227, 0.26);
}

.btn-primary:hover {
  background: var(--blue-hover);
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(0, 113, 227, 0.32);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-ghost {
  color: var(--blue);
  padding-inline: 18px;
}

.btn-ghost:hover {
  background: rgba(0, 113, 227, 0.07);
}

.btn-sm {
  height: 34px;
  padding-inline: 16px;
  font-size: 13.5px;
}

.btn-lg {
  height: 50px;
  padding-inline: 30px;
  font-size: 16px;
}

.eyebrow {
  display: inline-block;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.09em;
  color: var(--blue);
  text-transform: uppercase;
}

.eyebrow--light {
  color: rgba(255, 255, 255, 0.62);
}

.section {
  padding-block: clamp(68px, 9vw, 118px);
}

.section-alt {
  background: var(--surface-alt);
}

.section-head {
  max-width: 680px;
  margin-bottom: clamp(36px, 5vw, 56px);
}

.section-head h2 {
  margin-top: 12px;
  font-size: clamp(1.75rem, 3.4vw, 2.6rem);
}

.section-sub {
  margin-top: 14px;
  font-size: 16px;
  color: var(--muted);
}

.grad-text {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* 空 Logo 的渐变占位底 */
.logo-box {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  border-radius: 10px;
  background: var(--grad);
  overflow: hidden;
  box-shadow: 0 4px 12px rgba(109, 93, 252, 0.24);
}

.logo-box img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.logo-box--lg {
  width: 88px;
  height: 88px;
  border-radius: 24px;
  box-shadow: 0 18px 40px rgba(8, 15, 40, 0.45);
}

.logo-box--sm {
  width: 30px;
  height: 30px;
  border-radius: 9px;
  box-shadow: none;
}

/* --------------------------------------------------------------------------
   顶部导航
   -------------------------------------------------------------------------- */

.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--header-h);
  background: rgba(251, 251, 253, 0.72);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition: background-color 0.3s var(--ease), border-color 0.3s var(--ease),
    box-shadow 0.3s var(--ease);
}

.site-header.is-scrolled {
  background: rgba(251, 251, 253, 0.88);
  border-bottom-color: var(--line);
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.02);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.brand-name {
  display: flex;
  flex-direction: column;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.15;
}

.brand-name small {
  font-size: 10.5px;
  font-weight: 500;
  color: var(--faint);
  letter-spacing: 0.04em;
}

.nav {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 30px);
}

.nav-link {
  position: relative;
  font-size: 14px;
  color: var(--muted);
  transition: color 0.2s ease;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -8px;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--blue);
  opacity: 0;
  transform: translate(-50%, 4px);
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.nav-link:hover {
  color: var(--ink);
}

.nav-link.is-current {
  color: var(--ink);
  font-weight: 500;
}

.nav-link.is-current::after {
  opacity: 1;
  transform: translate(-50%, 0);
}

.nav-link--download {
  display: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: 9px;
}

.nav-toggle span {
  display: block;
  width: 17px;
  height: 1.6px;
  margin-inline: auto;
  border-radius: 2px;
  background: var(--ink);
  transition: transform 0.25s var(--ease), opacity 0.2s ease;
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(5.6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-5.6px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   首屏
   -------------------------------------------------------------------------- */

.hero {
  position: relative;
  padding-top: calc(var(--header-h) + clamp(56px, 8vw, 92px));
  padding-bottom: clamp(56px, 8vw, 104px);
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(10px);
  pointer-events: none;
  z-index: 0;
}

.hero-glow--sky {
  top: -28%;
  right: -12%;
  width: min(62vw, 760px);
  aspect-ratio: 1;
  background: radial-gradient(circle, rgba(124, 199, 247, 0.38) 0%, rgba(124, 199, 247, 0) 66%);
}

.hero-glow--violet {
  bottom: -40%;
  left: -18%;
  width: min(58vw, 700px);
  aspect-ratio: 1;
  background: radial-gradient(circle, rgba(167, 139, 250, 0.3) 0%, rgba(167, 139, 250, 0) 68%);
}

.hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.06fr) minmax(0, 0.94fr);
  align-items: center;
  gap: clamp(32px, 4vw, 64px);
}

.hero-copy {
  max-width: 620px;
}

.eyebrow-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px 7px 12px;
  border-radius: 980px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(0, 0, 0, 0.06);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  font-size: 12.5px;
  font-weight: 500;
  color: var(--muted);
  box-shadow: var(--shadow-xs);
}

.dot-live {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #30d158;
  box-shadow: 0 0 0 3px rgba(48, 209, 88, 0.18);
}

.hero h1 {
  margin-top: 22px;
  font-size: clamp(2rem, 7vw, 3.25rem);
  font-weight: 700;
  letter-spacing: -0.032em;
  line-height: 1.11;
}

.lead {
  margin-top: 20px;
  max-width: 36em;
  font-size: clamp(15px, 1.15vw, 17px);
  line-height: 1.78;
  color: var(--muted);
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 26px;
}

.meta-pill {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 8px 14px;
  border-radius: 12px;
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-xs);
  font-size: 12.5px;
  color: var(--faint);
}

.meta-pill strong {
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.hero-points {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  margin-top: 26px;
  font-size: 13.5px;
  color: var(--muted);
}

.hero-points li {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.hero-points span {
  color: var(--blue);
  font-weight: 700;
  font-size: 12px;
}

/* 三张截图叠加 */
.hero-visual {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.shot-stack {
  position: relative;
  width: 100%;
  height: clamp(430px, 39vw, 520px);
}

.shot {
  position: absolute;
  left: 50%;
  top: 50%;
  width: clamp(180px, 17.5vw, 224px);
  aspect-ratio: 9 / 19.3;
  padding: 0;
  border-radius: 26px;
  border: 1px solid rgba(255, 255, 255, 0.9);
  background: linear-gradient(155deg, #eef5ff 0%, #e8e2fc 100%);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  cursor: pointer;
  z-index: 1;
  transform: translate(-50%, -50%) translate(var(--x, 0), var(--y, 0)) rotate(var(--rot, 0deg))
    scale(var(--scale, 1));
  transition: transform 0.55s var(--ease), box-shadow 0.55s var(--ease),
    border-color 0.3s ease;
  -webkit-tap-highlight-color: transparent;
}

.shot-1 {
  --x: -47%;
  --y: 2%;
  --rot: -9deg;
  --scale: 0.9;
}

.shot-2 {
  --x: 0%;
  --y: -2%;
  --rot: 0deg;
  --scale: 1;
  z-index: 2;
}

.shot-3 {
  --x: 47%;
  --y: 2%;
  --rot: 9deg;
  --scale: 0.9;
}

.shot:hover,
.shot:focus-visible,
.shot.is-active {
  --x: 0%;
  --y: -6%;
  --rot: 0deg;
  --scale: 1.055;
  z-index: 10;
  border-color: rgba(255, 255, 255, 1);
  box-shadow: 0 34px 70px rgba(30, 34, 60, 0.22), 0 0 0 1px rgba(109, 93, 252, 0.08);
}

.shot img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 2;
}

.shot-fallback {
  position: absolute;
  inset: 0;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  color: #5b5f7a;
}

.shot-fallback::before {
  content: "";
  position: absolute;
  inset: 14px;
  border-radius: 16px;
  border: 1px dashed rgba(91, 95, 122, 0.28);
}

.shot-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  margin-bottom: 4px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.82);
  box-shadow: 0 6px 16px rgba(91, 95, 122, 0.16);
  font-size: 15px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: #6a5cf0;
}

.shot-caption {
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.shot-note {
  font-size: 10.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #8c90a8;
}

.shot-hint {
  margin-top: 18px;
  font-size: 12.5px;
  color: var(--faint);
}

/* --------------------------------------------------------------------------
   功能
   -------------------------------------------------------------------------- */

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(14px, 1.8vw, 20px);
}

.feature-card {
  position: relative;
  padding: clamp(24px, 2.6vw, 32px);
  border-radius: var(--radius-md);
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-xs);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease),
    border-color 0.35s var(--ease);
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(109, 93, 252, 0.22);
  box-shadow: var(--shadow-sm);
}

.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 13px;
  color: var(--blue);
  background: linear-gradient(140deg, rgba(124, 199, 247, 0.18), rgba(167, 139, 250, 0.18));
  border: 1px solid rgba(109, 93, 252, 0.1);
}

.feature-card h3 {
  margin-top: 18px;
  font-size: 18.5px;
}

.feature-card p {
  margin-top: 10px;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--muted);
}

.spec-strip {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(28px, 4vw, 44px);
  padding: 6px;
  border-radius: var(--radius-md);
  background: rgba(0, 0, 0, 0.055);
  border: 1px solid var(--line);
  overflow: hidden;
}

.spec-item {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 18px 20px;
  background: var(--bg);
  border-radius: 14px;
  text-align: center;
}

.spec-label {
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--faint);
}

.spec-value {
  font-size: 14.5px;
  font-weight: 600;
  color: var(--ink);
}

/* --------------------------------------------------------------------------
   教程
   -------------------------------------------------------------------------- */

.notice {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  max-width: 880px;
  margin-bottom: clamp(36px, 5vw, 56px);
  padding: 18px 22px;
  border-radius: var(--radius-sm);
  background: rgba(0, 113, 227, 0.055);
  border: 1px solid rgba(0, 113, 227, 0.16);
}

.notice-icon {
  display: inline-flex;
  flex: 0 0 auto;
  color: var(--blue);
  margin-top: 1px;
}

.notice p {
  font-size: 14.5px;
  line-height: 1.72;
  color: #33506e;
}

.notice strong {
  color: #12446e;
}

.steps {
  display: flex;
  flex-direction: column;
  gap: clamp(44px, 6vw, 72px);
}

.step {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 0.82fr);
  align-items: center;
  gap: clamp(28px, 4.5vw, 64px);
}

.step:nth-child(even) .step-media {
  order: -1;
}

.step-body {
  max-width: 560px;
}

.step-no {
  display: block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  font-variant-numeric: tabular-nums;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.step-body h3 {
  margin-top: 10px;
  font-size: clamp(1.2rem, 2vw, 1.5rem);
}

.step-body p {
  margin-top: 12px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.step-list {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.step-list li {
  position: relative;
  padding-left: 18px;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--faint);
}

.step-list li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 0.62em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: rgba(109, 93, 252, 0.42);
}

.step-media {
  margin: 0;
  justify-self: end;
  width: 100%;
  max-width: 380px;
  padding: 10px;
  border-radius: 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-md);
}

.step:nth-child(even) .step-media {
  justify-self: start;
}

.step-media img {
  width: 100%;
  height: auto;
  border-radius: 15px;
  background: var(--surface-alt);
}

.step-media.is-broken {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 260px;
}

.step-media.is-broken img {
  display: none;
}

.step-media.is-broken::after {
  content: "示意图暂时无法加载";
  font-size: 13px;
  color: var(--faint);
}

.tutorial-tips {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(14px, 2vw, 20px);
  margin-top: clamp(48px, 6vw, 76px);
}

.tip-card {
  padding: 24px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--line);
}

.tip-card h3 {
  font-size: 15.5px;
}

.tip-card p {
  margin-top: 9px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   用户评价
   -------------------------------------------------------------------------- */

.review-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(14px, 2vw, 22px);
}

.review-card {
  display: flex;
  flex-direction: column;
  padding: clamp(24px, 2.6vw, 32px);
  border-radius: var(--radius-md);
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-xs);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease);
}

.review-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-sm);
}

.stars {
  font-size: 14px;
  letter-spacing: 0.14em;
  color: #f0a02c;
}

.stars-off {
  color: #d8d8dd;
}

.review-text {
  flex: 1;
  margin-top: 14px;
  font-size: 15px;
  line-height: 1.8;
  color: #3c3c40;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 20px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--grad);
  color: #fff;
  font-size: 15px;
  font-weight: 600;
  box-shadow: 0 6px 14px rgba(109, 93, 252, 0.26);
}

.avatar--violet {
  background: linear-gradient(140deg, #9b7bf7, #c48bf2);
  box-shadow: 0 6px 14px rgba(155, 123, 247, 0.26);
}

.avatar--sky {
  background: linear-gradient(140deg, #4aa8f0, #7cc7f7);
  box-shadow: 0 6px 14px rgba(74, 168, 240, 0.26);
}

.avatar--ink {
  background: linear-gradient(140deg, #3a3a3f, #63636b);
  box-shadow: 0 6px 14px rgba(58, 58, 63, 0.24);
}

.review-user-info {
  display: flex;
  flex-direction: column;
  line-height: 1.4;
}

.review-user-info strong {
  font-size: 14.5px;
  font-weight: 600;
}

.review-user-info span {
  font-size: 12.5px;
  color: var(--faint);
}

/* --------------------------------------------------------------------------
   FAQ
   -------------------------------------------------------------------------- */

.faq-list {
  max-width: 860px;
}

.faq-item {
  margin-bottom: 10px;
  border-radius: var(--radius-sm);
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-xs);
  overflow: hidden;
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.faq-item[open] {
  border-color: rgba(109, 93, 252, 0.2);
  box-shadow: var(--shadow-sm);
}

.faq-item summary {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 19px 56px 19px 24px;
  font-size: 15.5px;
  font-weight: 500;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
  transition: color 0.2s ease;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary:hover {
  color: var(--blue);
}

.faq-item summary::after {
  content: "";
  position: absolute;
  right: 24px;
  top: 50%;
  width: 11px;
  height: 11px;
  margin-top: -6px;
  border-right: 1.6px solid var(--faint);
  border-bottom: 1.6px solid var(--faint);
  transform: rotate(45deg);
  transition: transform 0.3s var(--ease);
}

.faq-item[open] summary::after {
  transform: rotate(-135deg);
  border-color: var(--blue);
}

.faq-body {
  padding: 0 24px 22px;
  animation: faqFade 0.35s var(--ease);
}

.faq-body p {
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
}

@keyframes faqFade {
  from {
    opacity: 0;
    transform: translateY(-4px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* --------------------------------------------------------------------------
   下载
   -------------------------------------------------------------------------- */

.download-section {
  padding-block: clamp(48px, 6vw, 80px);
  background: var(--bg);
}

.download-panel {
  position: relative;
  padding: clamp(48px, 7.5vw, 92px) clamp(24px, 4vw, 64px);
  border-radius: clamp(28px, 3vw, 40px);
  background: #101014;
  background-image: radial-gradient(120% 120% at 50% 0%, #1c1c24 0%, #0b0b0e 62%);
  overflow: hidden;
  text-align: center;
  box-shadow: 0 40px 80px rgba(12, 14, 32, 0.22);
}

.download-glow {
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
}

.download-glow--sky {
  top: -38%;
  left: 8%;
  width: 52%;
  aspect-ratio: 1;
  background: radial-gradient(circle, rgba(79, 172, 254, 0.34) 0%, rgba(79, 172, 254, 0) 68%);
}

.download-glow--violet {
  bottom: -46%;
  right: 2%;
  width: 56%;
  aspect-ratio: 1;
  background: radial-gradient(circle, rgba(167, 139, 250, 0.32) 0%, rgba(167, 139, 250, 0) 70%);
}

.download-content {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.download-content h2 {
  max-width: 16em;
  margin-top: 18px;
  color: #fff;
  font-size: clamp(1.8rem, 3.9vw, 2.85rem);
  letter-spacing: -0.028em;
}

.download-desc {
  max-width: 34em;
  margin-top: 14px;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.6);
}

.download-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-top: 26px;
  font-size: 12.5px;
  color: rgba(255, 255, 255, 0.5);
}

.download-meta strong {
  font-size: 13.5px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.92);
  font-variant-numeric: tabular-nums;
}

.meta-dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.28);
}

.btn-download {
  height: 58px;
  margin-top: 34px;
  padding: 0 40px;
  border-radius: 980px;
  background: #fff;
  color: #101014;
  font-size: 16.5px;
  font-weight: 600;
  box-shadow: 0 14px 34px rgba(255, 255, 255, 0.16), 0 2px 0 rgba(0, 0, 0, 0.06);
}

.btn-download:hover {
  background: #f2f2f5;
  transform: translateY(-2px) scale(1.015);
  box-shadow: 0 20px 44px rgba(255, 255, 255, 0.2);
}

.btn-download:active {
  transform: translateY(0) scale(1);
}

.download-hint {
  margin-top: 20px;
  font-size: 12px;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.38);
}

/* --------------------------------------------------------------------------
   页脚
   -------------------------------------------------------------------------- */

.site-footer {
  padding-block: clamp(40px, 5vw, 64px);
  background: var(--surface-alt);
  border-top: 1px solid var(--line);
}

.footer-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 32px;
  align-items: start;
}

.footer-brand {
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.footer-brand strong {
  font-size: 15px;
  font-weight: 700;
}

.footer-brand p {
  margin-top: 4px;
  font-size: 12.5px;
  color: var(--faint);
  line-height: 1.6;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  font-size: 13px;
  color: var(--muted);
}

.footer-nav a:hover {
  color: var(--ink);
}

.footer-meta {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--faint);
}

.footer-meta a {
  color: var(--muted);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: rgba(0, 0, 0, 0.18);
}

.footer-meta a:hover {
  color: var(--blue);
}

/* --------------------------------------------------------------------------
   Toast
   -------------------------------------------------------------------------- */

.toast {
  position: fixed;
  left: 50%;
  bottom: 28px;
  z-index: 200;
  padding: 12px 22px;
  border-radius: 980px;
  background: rgba(29, 29, 31, 0.92);
  color: #fff;
  font-size: 13.5px;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.24);
  opacity: 0;
  transform: translate(-50%, 14px);
  pointer-events: none;
  transition: opacity 0.3s var(--ease), transform 0.3s var(--ease);
}

.toast.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* --------------------------------------------------------------------------
   滚动入场
   -------------------------------------------------------------------------- */

.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.75s var(--ease), transform 0.75s var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* --------------------------------------------------------------------------
   响应式
   -------------------------------------------------------------------------- */

@media (max-width: 1024px) {
  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .spec-strip {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .spec-item:nth-child(4),
  .spec-item:nth-child(5) {
    grid-column: auto;
  }
}

@media (max-width: 960px) {
  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    z-index: 90;
    flex-direction: column;
    align-items: flex-start;
    gap: 2px;
    padding: 14px clamp(20px, 5vw, 40px) 22px;
    background: rgba(251, 251, 253, 0.96);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 24px 40px rgba(0, 0, 0, 0.08);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.28s var(--ease), transform 0.28s var(--ease),
      visibility 0.28s;
  }

  .nav.is-open {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .nav-link {
    width: 100%;
    padding: 13px 0;
    font-size: 16px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.055);
  }

  .nav-link:last-child {
    border-bottom: 0;
  }

  .nav-link::after {
    display: none;
  }

  .nav-link--download {
    display: block;
    color: var(--blue);
  }

  .nav-toggle {
    display: flex;
  }

  .nav-download {
    display: none;
  }

  .hero-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: clamp(36px, 5vw, 52px);
  }

  .hero-copy {
    max-width: 640px;
  }

  .hero-visual {
    order: 2;
  }

  .shot-stack {
    height: clamp(400px, 62vw, 480px);
  }

  .shot {
    width: clamp(162px, 27vw, 220px);
  }

  .shot-1 {
    --x: -34%;
  }

  .shot-3 {
    --x: 34%;
  }

  .step {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
  }

  .step:nth-child(even) .step-media {
    order: 0;
  }

  .step-media {
    justify-self: stretch;
    max-width: 440px;
    margin-inline: auto;
  }

  .step:nth-child(even) .step-media {
    justify-self: center;
  }

  .tutorial-tips {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 28px;
  }

  .footer-meta {
    grid-column: 1 / -1;
  }
}

@media (max-width: 760px) {
  .section-head h2 {
    font-size: clamp(1.6rem, 6vw, 2rem);
  }

  .feature-grid,
  .review-grid,
  .tutorial-tips {
    grid-template-columns: minmax(0, 1fr);
  }

  .spec-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .spec-item:last-child {
    grid-column: 1 / -1;
  }

  .spec-item {
    padding: 15px 12px;
  }

  .hero-actions .btn {
    flex: 1 1 auto;
  }

  .shot-stack {
    height: clamp(390px, 104vw, 470px);
  }

  .shot {
    width: min(50vw, 210px);
    border-radius: 24px;
  }

  .shot-1 {
    --x: -30%;
    --rot: -7deg;
  }

  .shot-3 {
    --x: 30%;
    --rot: 7deg;
  }

  .shot-hint {
    margin-top: 14px;
  }

  .notice {
    padding: 16px 18px;
  }

  .review-card,
  .feature-card {
    padding: 22px;
  }

  .faq-item summary {
    padding: 16px 48px 16px 18px;
    font-size: 15px;
  }

  .faq-item summary::after {
    right: 20px;
  }

  .faq-body {
    padding: 0 18px 18px;
  }

  .download-panel {
    padding: 44px 22px 52px;
  }

  .download-content h2 {
    font-size: clamp(1.55rem, 7vw, 2rem);
  }

  .btn-download {
    width: 100%;
    max-width: 340px;
    height: 56px;
    padding-inline: 20px;
  }

  .download-meta {
    gap: 7px;
    font-size: 11.5px;
  }

  .download-meta strong {
    font-size: 12.5px;
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
  }

  .toast {
    bottom: 18px;
    max-width: calc(100vw - 40px);
    text-align: center;
    border-radius: 18px;
  }
}

@media (max-width: 380px) {
  .meta-pill {
    padding: 7px 11px;
  }

  .shot-stack {
    height: 372px;
  }

  .step-media {
    border-radius: 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}