:root {
  --ink: #142033;
  --ink-soft: #5a6578;
  --paper: #f3f7fb;
  --card: #ffffff;
  --line: rgba(20, 32, 51, 0.08);
  --sky: #1f6bff;
  --sky-deep: #1554d4;
  --teal: #0f8f7b;
  --warm: #f4ebe0;
  --shadow: 0 18px 48px rgba(31, 107, 255, 0.12);
  --radius: 22px;
  --font-display: "Noto Serif SC", "Songti SC", serif;
  --font-ui: "Noto Sans SC", "PingFang SC", sans-serif;
  --max: 1080px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-ui);
  background:
    radial-gradient(90% 55% at 85% -5%, rgba(31, 107, 255, 0.18), transparent 55%),
    radial-gradient(70% 45% at 0% 10%, rgba(15, 143, 123, 0.1), transparent 50%),
    linear-gradient(180deg, #dceafc 0%, var(--paper) 42%, #eef3f8 100%);
  -webkit-font-smoothing: antialiased;
}

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

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

.wrap {
  width: min(var(--max), calc(100% - 2rem));
  margin-inline: auto;
}

/* —— Top —— */
.top {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(16px) saturate(1.2);
  background: rgba(243, 247, 251, 0.78);
  border-bottom: 1px solid rgba(255, 255, 255, 0.55);
}

.top__inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.brand__mark {
  width: 36px;
  height: 36px;
  border-radius: 11px;
  background: linear-gradient(145deg, #6aa8ff, #1f6bff 55%, #0f8f7b);
  box-shadow: 0 8px 18px rgba(31, 107, 255, 0.28);
}

.brand__text {
  font-family: var(--font-display);
  font-size: 1.15rem;
}

.top__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1rem;
  font-size: 0.92rem;
  font-weight: 650;
  color: var(--ink-soft);
}

.top__nav a:hover {
  color: var(--sky-deep);
}

/* —— Hero —— */
.hero {
  position: relative;
  min-height: min(92vh, 820px);
  display: grid;
  align-items: end;
  overflow: hidden;
  isolation: isolate;
}

.hero__media {
  position: absolute;
  inset: 0;
  z-index: -2;
}

.hero__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 58% 42%;
  transform: scale(1.02);
}

.hero__veil {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(180deg, rgba(12, 28, 52, 0.18) 0%, rgba(12, 28, 52, 0.55) 52%, rgba(12, 28, 52, 0.78) 100%),
    linear-gradient(90deg, rgba(12, 28, 52, 0.55) 0%, rgba(12, 28, 52, 0.12) 62%, transparent 100%);
}

.hero__inner {
  padding: 7.5rem 0 3.4rem;
  color: #f7fbff;
  max-width: 36rem;
}

.hero__brand {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(2.6rem, 8vw, 3.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.12;
  text-shadow: 0 10px 40px rgba(0, 0, 0, 0.28);
}

.hero__lead {
  margin: 0 0 1.6rem;
  font-size: clamp(1.05rem, 2.8vw, 1.25rem);
  line-height: 1.65;
  color: rgba(247, 251, 255, 0.9);
  max-width: 28rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 48px;
  padding: 0.7rem 1.25rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font: inherit;
  font-weight: 750;
  cursor: pointer;
  transition: transform 0.18s ease, background 0.18s ease, border-color 0.18s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn--primary {
  background: #fff;
  color: var(--ink);
  box-shadow: 0 12px 28px rgba(0, 0, 0, 0.18);
}

.btn--ghost {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.35);
  color: #fff;
  backdrop-filter: blur(8px);
}

.btn--soon {
  position: relative;
  opacity: 0.92;
  cursor: default;
}

.btn--soon::after {
  content: "即将上架";
  margin-left: 0.35rem;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  opacity: 0.8;
}

.btn--solid {
  background: var(--sky);
  color: #fff;
  box-shadow: 0 12px 28px rgba(31, 107, 255, 0.28);
}

.btn--solid:hover {
  background: var(--sky-deep);
}

.btn--line {
  background: #fff;
  border-color: var(--line);
  color: var(--ink);
}

/* —— Sections —— */
.section {
  padding: 4.5rem 0;
}

.section__head {
  max-width: 34rem;
  margin-bottom: 1.8rem;
}

.section__head h2 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 4vw, 2.2rem);
  letter-spacing: -0.02em;
  line-height: 1.25;
}

.section__head p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.7;
  font-size: 1.02rem;
}

.panel {
  background: rgba(255, 255, 255, 0.82);
  border: 1px solid rgba(255, 255, 255, 0.9);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.35rem 1.25rem;
}

.steps {
  display: grid;
  gap: 0.9rem;
}

@media (min-width: 780px) {
  .steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

.step {
  padding: 1.25rem 1.15rem 1.3rem;
  border-radius: 18px;
  background: #fff;
  border: 1px solid var(--line);
}

.step__n {
  display: inline-grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border-radius: 999px;
  margin-bottom: 0.85rem;
  background: rgba(31, 107, 255, 0.1);
  color: var(--sky-deep);
  font-weight: 850;
  font-size: 0.9rem;
}

.step h3 {
  margin: 0 0 0.4rem;
  font-size: 1.12rem;
}

.step p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.65;
  font-size: 0.95rem;
}

/* —— 痛点专区：浅底四卡 —— */
.problems {
  padding: 4.2rem 0 4.4rem;
  background: #eef1f5;
}

.problems__intro {
  text-align: center;
  max-width: 46rem;
  margin: 0 auto 2.2rem;
}

.problems__title {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 3.2vw, 1.7rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.35;
  color: var(--ink-soft);
}

.problems__lead {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.45rem, 4.2vw, 2.05rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.45;
  color: var(--ink);
}

.problems__lead strong {
  font-weight: 900;
  color: var(--sky-deep);
  white-space: nowrap;
}

.pain-grid {
  display: grid;
  gap: 0.9rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .pain-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 980px) {
  .pain-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1rem;
  }
}

.pain-card {
  perspective: 1100px;
  min-height: 230px;
  border-radius: 16px;
}

.pain-card__inner {
  position: relative;
  width: 100%;
  height: 100%;
  min-height: 230px;
  transform-style: preserve-3d;
  transition: transform 0.55s cubic-bezier(0.22, 0.8, 0.28, 1);
}

.pain-card:hover .pain-card__inner,
.pain-card:focus-within .pain-card__inner {
  transform: rotateY(180deg);
}

.pain-card__face {
  position: absolute;
  inset: 0;
  display: grid;
  justify-items: center;
  align-content: center;
  text-align: center;
  gap: 0.85rem;
  padding: 1.45rem 1.15rem 1.35rem;
  border-radius: 16px;
  background: #fff;
  border: 1px solid rgba(20, 32, 51, 0.04);
  box-shadow: 0 10px 28px rgba(20, 32, 51, 0.06);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

.pain-card__face--front {
  grid-auto-rows: min-content;
}

.pain-card__face--back {
  transform: rotateY(180deg);
  padding: 1.6rem 1.25rem;
  align-content: center;
}

.pain-card__face--gold {
  background: linear-gradient(160deg, #fffaf0, #fff3c9);
  border-color: rgba(212, 160, 23, 0.18);
}

.pain-card__face--green {
  background: linear-gradient(160deg, #f3fcf7, #d9f5e4);
  border-color: rgba(47, 157, 106, 0.18);
}

.pain-card__face--blue {
  background: linear-gradient(160deg, #f4f8ff, #dcecff);
  border-color: rgba(43, 111, 232, 0.18);
}

.pain-card__face--violet {
  background: linear-gradient(160deg, #f7f4ff, #ebe4ff);
  border-color: rgba(124, 92, 255, 0.18);
}

.pain-card h3 {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.pain-card__face--front p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.55;
  color: #6b7280;
  max-width: 16rem;
}

.pain-card__face--back p {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.05rem, 1.6vw, 1.18rem);
  font-weight: 700;
  line-height: 1.65;
  color: var(--ink);
  max-width: 17rem;
}

.pain-card__face--gold p {
  color: #8a6410;
}

.pain-card__face--green p {
  color: #1f6b48;
}

.pain-card__face--blue p {
  color: #1a4fb8;
}

.pain-card__face--violet p {
  color: #4f35b8;
}

.pain-card__icon {
  width: 58px;
  height: 58px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  position: relative;
}

.pain-card__icon--gold {
  background: #fff3c9;
}

.pain-card__icon--green {
  background: #d9f5e4;
}

.pain-card__icon--blue {
  background: #dcecff;
}

.pain-card__icon--violet {
  background: #ebe4ff;
}

.glyph {
  width: 26px;
  height: 26px;
  position: relative;
  display: block;
}

.glyph--clock {
  border: 2.5px solid #d4a017;
  border-radius: 50%;
}

.glyph--clock::before,
.glyph--clock::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  background: #d4a017;
  border-radius: 999px;
}

.glyph--clock::before {
  width: 2px;
  height: 8px;
  margin: -8px 0 0 -1px;
}

.glyph--clock::after {
  width: 6px;
  height: 2px;
  margin: -1px 0 0 0;
}

.glyph--loop {
  border: 2.5px solid #2f9d6a;
  border-radius: 50%;
  border-top-color: transparent;
  transform: rotate(-30deg);
}

.glyph--loop::after {
  content: "";
  position: absolute;
  top: -2px;
  right: 1px;
  border: 5px solid transparent;
  border-bottom-color: #2f9d6a;
  transform: rotate(55deg);
}

.glyph--scatter {
  width: 22px;
  height: 22px;
}

.glyph--scatter::before,
.glyph--scatter::after {
  content: "";
  position: absolute;
  border-radius: 3px;
  background: #2b6fe8;
}

.glyph--scatter::before {
  width: 9px;
  height: 12px;
  left: 0;
  top: 2px;
  transform: rotate(-14deg);
}

.glyph--scatter::after {
  width: 8px;
  height: 11px;
  right: 0;
  bottom: 1px;
  background: #5b8cff;
  transform: rotate(16deg);
  box-shadow: -9px -7px 0 #93b8ff;
}

.glyph--drain::before {
  content: "";
  position: absolute;
  left: 3px;
  right: 3px;
  top: 4px;
  height: 7px;
  border-radius: 5px 5px 2px 2px;
  background: #7c5cff;
}

.glyph--drain::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 11px;
  width: 2.5px;
  height: 11px;
  margin-left: -1.25px;
  background: linear-gradient(#7c5cff, transparent);
  box-shadow: -5px 2px 0 #b39bff, 5px 3px 0 #b39bff;
}

@media (prefers-reduced-motion: reduce) {
  .pain-card__inner {
    transition: none;
  }

  .pain-card:hover .pain-card__inner,
  .pain-card:focus-within .pain-card__inner {
    transform: none;
  }

  .pain-card__face--back {
    display: none;
  }
}

/* 触屏：点击切换翻转 */
@media (hover: none) {
  .pain-card.is-flipped .pain-card__inner {
    transform: rotateY(180deg);
  }
}

.feature {
  display: grid;
  gap: 1.4rem;
  align-items: center;
}

@media (min-width: 860px) {
  .feature {
    grid-template-columns: 1.05fr 0.95fr;
    gap: 2.2rem;
  }

  .feature--flip {
    grid-template-columns: 0.95fr 1.05fr;
  }

  .feature--flip .feature__copy {
    order: 2;
  }
}

.feature__copy h2 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 3.5vw, 2rem);
  letter-spacing: -0.02em;
}

.feature__copy p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.75;
  font-size: 1.02rem;
}

.feature__visual {
  min-height: 240px;
  border-radius: 20px;
  border: 1px solid var(--line);
  background:
    linear-gradient(160deg, rgba(31, 107, 255, 0.1), rgba(15, 143, 123, 0.08)),
    #fff;
  padding: 1.4rem;
  display: grid;
  align-content: center;
  gap: 0.7rem;
  box-shadow: var(--shadow);
}

.chip {
  display: inline-flex;
  width: fit-content;
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  background: rgba(31, 107, 255, 0.08);
  color: var(--sky-deep);
  font-size: 0.86rem;
  font-weight: 750;
}

.fake-sheet {
  border-radius: 14px;
  background: linear-gradient(180deg, #fff, #f7fafc);
  border: 1px solid var(--line);
  padding: 1rem 1.05rem;
}

.fake-sheet strong {
  display: block;
  margin-bottom: 0.45rem;
  font-size: 0.95rem;
}

.fake-sheet p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.88rem;
  line-height: 1.6;
}

.line {
  height: 8px;
  border-radius: 999px;
  background: #e7eef7;
  margin-top: 0.55rem;
}

.line--short {
  width: 62%;
}

.download {
  background:
    radial-gradient(80% 80% at 100% 0%, rgba(31, 107, 255, 0.12), transparent 55%),
    #fff;
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 4px);
  padding: 1.6rem 1.35rem;
  box-shadow: var(--shadow);
}

.download__grid {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.2rem;
}

@media (min-width: 720px) {
  .download__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.download__card {
  display: grid;
  gap: 0.35rem;
  padding: 1rem 1rem 1.05rem;
  border-radius: 16px;
  background: var(--paper);
  border: 1px dashed rgba(31, 107, 255, 0.22);
  min-height: 118px;
}

.download__card strong {
  font-size: 1.02rem;
}

.download__card span {
  color: var(--ink-soft);
  font-size: 0.88rem;
  line-height: 1.5;
}

.download__card em {
  margin-top: auto;
  font-style: normal;
  font-size: 0.78rem;
  font-weight: 750;
  color: var(--teal);
}

.teacher {
  display: grid;
  gap: 1rem;
}

@media (min-width: 780px) {
  .teacher {
    grid-template-columns: 1.3fr 0.7fr;
    align-items: stretch;
  }
}

.teacher__aside {
  display: grid;
  place-items: center;
  text-align: center;
  padding: 1.4rem;
  border-radius: var(--radius);
  background: linear-gradient(160deg, #16325f, #1f6bff 70%, #0f8f7b);
  color: #fff;
  box-shadow: var(--shadow);
}

.teacher__aside strong {
  display: block;
  font-family: var(--font-display);
  font-size: 1.45rem;
  margin-bottom: 0.4rem;
}

.teacher__aside p {
  margin: 0 0 1rem;
  opacity: 0.9;
  line-height: 1.6;
  font-size: 0.92rem;
}

/* —— Legal pages —— */
.doc {
  padding: 2.2rem 0 3.5rem;
}

.doc__card {
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: clamp(1.25rem, 3vw, 2rem);
  max-width: 44rem;
  margin: 0 auto;
}

.doc__card h1 {
  margin: 0.4rem 0 0.75rem;
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 4vw, 1.9rem);
}

.doc__card .meta {
  margin: 0 0 1.4rem;
  color: var(--ink-soft);
  font-size: 0.92rem;
  line-height: 1.7;
}

.doc__card h2 {
  margin: 1.5rem 0 0.55rem;
  font-size: 1.1rem;
}

.doc__card p,
.doc__card li {
  color: #2a3548;
  line-height: 1.75;
}

.doc__card ul {
  padding-left: 1.2rem;
}

.doc__back {
  display: inline-flex;
  color: var(--sky-deep);
  font-weight: 750;
}

/* —— Footer —— */
.footer {
  padding: 2.4rem 0 2.1rem;
  border-top: 1px solid rgba(20, 32, 51, 0.06);
  background: rgba(255, 255, 255, 0.45);
}

.footer__inner {
  display: grid;
  gap: 1rem;
}

.footer__brand {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.15rem;
}

.footer__links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.1rem;
  color: var(--ink-soft);
  font-size: 0.92rem;
  font-weight: 650;
}

.footer__links a:hover {
  color: var(--sky-deep);
}

.footer__meta {
  color: #7a8496;
  font-size: 0.84rem;
  line-height: 1.7;
}

.footer__meta a {
  color: #5a6578;
  border-bottom: 1px solid rgba(90, 101, 120, 0.35);
}

.footer__meta a:hover {
  color: var(--sky-deep);
}

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

  .btn:hover {
    transform: none;
  }
}