/* 库哥AI 官网 — 墨底碧芯 */
:root {
  --ink: #264653;
  --teal: #2a9d8f;
  --teal-deep: #1f7a70;
  --gold: #e9c46a;
  --sand: #f4a261;
  --coral: #e76f51;
  --paper: #f3f6f5;
  --paper-2: #e7efed;
  --fg: #1a2f36;
  --muted: #4a646c;
  --line: rgba(38, 70, 83, 0.14);
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Noto Sans SC", "WenQuanYi Micro Hei", sans-serif;
  --font-display: "Songti SC", "STSong", "SimSun", "Noto Serif SC", "PingFang SC", "Microsoft YaHei", serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--fg);
  font-family: var(--font-sans);
  background:
    radial-gradient(120% 80% at 100% 0%, rgba(42, 157, 143, 0.12), transparent 50%),
    radial-gradient(90% 60% at 0% 30%, rgba(233, 196, 106, 0.1), transparent 45%),
    linear-gradient(180deg, #eef5f3 0%, var(--paper) 40%, #e9f0ee 100%);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

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

.wrap {
  width: min(1120px, calc(100% - 2.5rem));
  margin-inline: auto;
}

.wrap.narrow {
  width: min(720px, calc(100% - 2.5rem));
}

/* Header */
.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem clamp(1rem, 3vw, 2rem);
  background: rgba(243, 246, 245, 0.72);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s var(--ease), background 0.3s var(--ease);
}

.site-header.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(243, 246, 245, 0.92);
}

.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.brand-lockup img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  object-fit: cover;
}

.site-nav {
  display: flex;
  gap: 1.25rem;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--muted);
}

.site-nav a {
  transition: color 0.2s var(--ease);
}

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

/* Hero: one composition, brand first, full-bleed media */
.hero {
  position: relative;
  min-height: 100svh;
  display: grid;
  align-items: end;
  color: #f7fbfa;
  overflow: hidden;
}

.hero-media {
  position: absolute;
  inset: 0;
}

.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 40%;
  transform: scale(1.04);
  animation: heroDrift 18s var(--ease) infinite alternate;
}

.hero-shade {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(18, 36, 42, 0.28) 0%, rgba(18, 36, 42, 0.15) 35%, rgba(18, 36, 42, 0.78) 100%),
    linear-gradient(90deg, rgba(38, 70, 83, 0.55) 0%, transparent 55%);
}

.hero-copy {
  position: relative;
  z-index: 1;
  width: min(720px, calc(100% - 2.5rem));
  margin: 0 auto 0 clamp(1rem, 4vw, 3rem);
  padding: 7rem 0 4.5rem;
  animation: riseIn 0.9s var(--ease) both;
}

.hero-brand {
  margin: 0 0 0.75rem;
  font-family: var(--font-display);
  font-size: clamp(2.6rem, 8vw, 4.4rem);
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.05;
  text-shadow: 0 2px 24px rgba(0, 0, 0, 0.25);
}

.hero-title {
  margin: 0;
  max-width: 18ch;
  font-family: var(--font-sans);
  font-size: clamp(1.35rem, 3.2vw, 1.85rem);
  font-weight: 600;
  line-height: 1.35;
  color: rgba(247, 251, 250, 0.96);
}

.hero-lead {
  margin: 0.9rem 0 0;
  max-width: 34ch;
  font-size: 1.02rem;
  color: rgba(236, 245, 243, 0.88);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.btn-primary,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.85rem;
  padding: 0.7rem 1.35rem;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: transform 0.2s var(--ease), background 0.2s var(--ease), border-color 0.2s var(--ease);
}

.btn-primary {
  background: var(--teal);
  color: #fff;
  border: 1px solid transparent;
}

.btn-primary:hover {
  background: var(--teal-deep);
  transform: translateY(-1px);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.35);
  color: #fff;
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.16);
}

.band-cta .btn-ghost-ink,
.btn-ghost-ink {
  background: transparent;
  border-color: var(--line);
  color: var(--ink);
}

.band-cta .btn-ghost-ink:hover,
.btn-ghost-ink:hover {
  border-color: var(--teal);
  background: rgba(42, 157, 143, 0.08);
}

.band-cta .btn-ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--ink);
}

.band-cta .btn-ghost:hover {
  border-color: var(--teal);
  background: rgba(42, 157, 143, 0.08);
}

.mobile-pc-tip {
  margin: 0;
  width: 100%;
  padding: 0.85rem 1rem;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  background: rgba(0, 0, 0, 0.28);
  color: rgba(247, 251, 250, 0.95);
  font-size: 0.92rem;
  font-weight: 500;
  line-height: 1.55;
  text-align: left;
}

.mobile-pc-tip-light {
  border-color: var(--line);
  background: rgba(38, 70, 83, 0.06);
  color: var(--ink);
  text-align: center;
}

.pc-req {
  margin: 1rem 0 0;
  font-size: 0.86rem;
  line-height: 1.5;
  color: rgba(236, 245, 243, 0.78);
}

.hero-pc-req {
  max-width: 36ch;
}

.pain-list {
  list-style: none;
  margin: 2rem auto 0;
  padding: 0;
  width: 100%;
  max-width: 36rem;
  display: grid;
  gap: 0.85rem;
  text-align: left;
}

.pain-item {
  list-style: none;
  margin: 0;
  padding: 1.05rem 1.15rem;
  border-left: 3px solid var(--teal);
  background: rgba(42, 157, 143, 0.06);
  text-align: left;
}

.pain-item strong {
  display: block;
  color: var(--ink);
  font-size: 1.05rem;
  font-weight: 650;
  text-align: left;
}

.pain-item span {
  display: block;
  margin-top: 0.4rem;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.6;
  text-align: left;
}

.pain-punch {
  margin: 1.75rem auto 0;
  max-width: 36rem;
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.55;
  text-align: center;
}

.pc-spec {
  margin: 1.5rem auto 0;
  max-width: 28rem;
  padding: 1.2rem 1.3rem;
  text-align: left;
  border: 1px solid var(--line);
  background: rgba(38, 70, 83, 0.04);
  border-radius: 12px;
}

.pc-spec-title {
  margin: 0 0 0.85rem;
  font-weight: 700;
  color: var(--ink);
  font-size: 0.98rem;
  text-align: left;
}

.pc-spec-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.65rem;
  text-align: left;
}

.pc-spec-list li {
  display: grid;
  grid-template-columns: 3.2em 1fr;
  gap: 0.5rem 0.65rem;
  align-items: start;
  margin: 0;
  padding: 0;
  list-style: none;
  text-align: left;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.55;
}

.pc-spec-list li strong {
  color: var(--ink);
  font-weight: 650;
  text-align: left;
}

.pc-spec-list li span {
  text-align: left;
}

/* 下载提醒弹层（手机点下载时） */
body.modal-open {
  overflow: hidden;
}

.dl-modal[hidden] {
  display: none !important;
}

.dl-modal {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: grid;
  place-items: center;
  padding: 1.25rem;
}

.dl-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(18, 36, 42, 0.55);
}

.dl-modal-panel {
  position: relative;
  z-index: 1;
  width: min(420px, 100%);
  padding: 1.5rem 1.35rem 1.25rem;
  border-radius: 14px;
  background: #fff;
  box-shadow: 0 18px 48px rgba(18, 36, 42, 0.22);
  text-align: left;
  animation: riseIn 0.35s var(--ease) both;
}

.dl-modal-panel h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.25rem;
  color: var(--ink);
}

.dl-modal-panel > p {
  margin: 0.75rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.dl-modal-spec {
  margin: 0.9rem 0 0;
  padding-left: 1.15rem;
  color: var(--ink);
  font-size: 0.92rem;
  font-weight: 500;
}

.dl-modal-spec li + li {
  margin-top: 0.3rem;
}

.dl-modal-tip {
  margin: 0.9rem 0 0 !important;
  padding: 0.7rem 0.85rem;
  border-radius: 8px;
  background: rgba(42, 157, 143, 0.1);
  color: var(--ink) !important;
  font-weight: 600;
  font-size: 0.9rem !important;
}

.dl-modal-ok {
  width: 100%;
  margin-top: 1.15rem;
  border: 0;
  cursor: pointer;
  font: inherit;
}

/* Sections */
.band {
  padding: clamp(3.5rem, 8vw, 5.5rem) 0;
}

.band-why {
  background:
    linear-gradient(180deg, rgba(38, 70, 83, 0.04), transparent),
    var(--paper);
  text-align: center;
}

.band-sells {
  background:
    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(42, 157, 143, 0.12), transparent 55%),
    var(--paper);
}

.section-head {
  margin-bottom: 2rem;
}

.section-head p {
  margin: 0.65rem 0 0;
  color: var(--muted);
  max-width: 36ch;
}

/* 必须写在 .section-head p 之后，否则 max-width/margin 会被盖掉导致「假左对齐」 */
.section-head-center {
  text-align: center;
  margin-inline: auto;
  max-width: 40rem;
}

.section-head-center h2 {
  text-align: center;
}

.section-head-center p {
  margin: 0.75rem auto 0;
  max-width: 32rem;
  text-align: center;
  line-height: 1.7;
  color: var(--muted);
}

.band-sells .section-head {
  margin-bottom: 1.75rem;
}

.sell-list {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  width: 100%;
  max-width: 920px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.9rem;
}

.sell-item {
  list-style: none;
  margin: 0;
  padding: 1.15rem 1.2rem;
  text-align: left;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--line);
  border-radius: 12px;
}

.sell-item:nth-child(5) {
  grid-column: 1 / -1;
  max-width: none;
}

.sell-item:first-child,
.sell-item:nth-child(2) {
  border-color: rgba(42, 157, 143, 0.45);
  background: rgba(42, 157, 143, 0.1);
  box-shadow: 0 0 0 1px rgba(42, 157, 143, 0.08);
}

.sell-item strong {
  display: block;
  color: var(--ink);
  font-size: 1.12rem;
  font-weight: 700;
  text-align: left;
}

.sell-item:first-child strong,
.sell-item:nth-child(2) strong {
  color: var(--teal-deep);
}

.sell-item span {
  display: block;
  margin-top: 0.45rem;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.6;
  text-align: left;
}

.band-why h2,
.section-head h2,
.band-cta h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.5vw, 2.25rem);
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.02em;
}

.band-lead {
  margin: 1rem auto 0;
  color: var(--muted);
  font-size: 1.05rem;
  max-width: 36rem;
  text-align: center;
  line-height: 1.7;
}

.feature-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0;
  border-top: 1px solid var(--line);
}

.feature-row {
  display: grid;
  gap: 0.25rem;
  padding: 1.15rem 1rem 1.15rem 0;
  border-bottom: 1px solid var(--line);
  transition: padding-left 0.25s var(--ease);
}

.feature-row:nth-child(even) {
  padding-left: 1.25rem;
  border-left: 1px solid var(--line);
}

.feature-row strong {
  font-size: 1.02rem;
  color: var(--ink);
  font-weight: 650;
}

.feature-row span {
  color: var(--muted);
  font-size: 0.92rem;
}

.feature-row:hover {
  padding-left: 0.35rem;
}

.feature-row:nth-child(even):hover {
  padding-left: 1.6rem;
}

.band-flow {
  background:
    linear-gradient(135deg, rgba(42, 157, 143, 0.08), transparent 40%),
    linear-gradient(180deg, var(--paper-2), var(--paper));
}

.flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.5rem;
}

.flow-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1rem;
  align-items: start;
}

.flow-n {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--teal);
  line-height: 1;
  padding-top: 0.15rem;
}

.flow-item h3 {
  margin: 0;
  font-size: 1.15rem;
  color: var(--ink);
}

.flow-item p {
  margin: 0.35rem 0 0;
  color: var(--muted);
}

.band-cta {
  text-align: center;
  background:
    radial-gradient(ellipse 70% 80% at 50% 100%, rgba(42, 157, 143, 0.16), transparent 60%),
    var(--paper);
}

.cta-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.cta-note {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.site-footer {
  padding: 1.75rem 0 2.25rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.88rem;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--ink);
  font-family: var(--font-display);
  font-weight: 700;
}

.footer-brand img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.site-footer p {
  margin: 0;
}

/* Motion */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  transition-delay: calc(var(--d, 0) * 40ms);
}

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

@keyframes riseIn {
  from {
    opacity: 0;
    transform: translateY(22px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes heroDrift {
  from {
    transform: scale(1.04) translate3d(0, 0, 0);
  }
  to {
    transform: scale(1.08) translate3d(0, -1.2%, 0);
  }
}

@media (min-width: 860px) {
  .flow-list {
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
  }

  .flow-item {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
}

@media (max-width: 860px) {
  .wrap {
    width: min(1120px, calc(100% - 1.75rem));
  }

  .wrap.narrow {
    width: min(720px, calc(100% - 1.75rem));
  }

  .sell-list {
    grid-template-columns: 1fr;
  }

  .sell-item:nth-child(5) {
    grid-column: auto;
  }
}

@media (max-width: 720px) {
  .site-nav {
    display: none;
  }

  .site-header {
    padding: 0.75rem 1rem;
  }

  .brand-lockup {
    font-size: 1.05rem;
  }

  .brand-lockup img {
    width: 32px;
    height: 32px;
  }

  .hero {
    min-height: 100svh;
    align-items: end;
  }

  .hero-copy {
    width: calc(100% - 1.75rem);
    margin: 0 auto;
    padding: 6.5rem 0 2.75rem;
  }

  .hero-brand {
    font-size: clamp(2.2rem, 12vw, 3rem);
  }

  .hero-title {
    max-width: none;
    font-size: clamp(1.2rem, 5.2vw, 1.45rem);
  }

  .hero-lead,
  .hero-pc-req {
    max-width: none;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
    gap: 0.65rem;
  }

  .hero-actions .btn-primary,
  .hero-actions .btn-ghost {
    width: 100%;
  }

  .band {
    padding: 3rem 0;
  }

  .section-head,
  .band-sells .section-head {
    margin-bottom: 1.35rem;
    text-align: left;
  }

  .band-sells .section-head-center,
  .band-why h2,
  .band-why .band-lead,
  .band-why .pain-punch,
  .band-cta h2,
  .band-cta .band-lead {
    text-align: center;
  }

  .section-head-center {
    max-width: none;
  }

  .section-head-center p {
    max-width: none;
    padding-inline: 0.15rem;
  }

  .band-lead {
    max-width: none;
    font-size: 0.98rem;
    padding-inline: 0.15rem;
  }

  .pain-list,
  .pain-punch,
  .pc-spec {
    max-width: none;
  }

  .pc-spec {
    padding: 1rem;
  }

  .pc-spec-list li {
    grid-template-columns: 2.8em 1fr;
    gap: 0.35rem 0.5rem;
    font-size: 0.88rem;
  }

  .feature-list {
    grid-template-columns: 1fr;
  }

  .feature-row,
  .feature-row:nth-child(even) {
    padding: 1rem 0;
    border-left: 0;
  }

  .feature-row:hover,
  .feature-row:nth-child(even):hover {
    padding-left: 0;
  }

  .flow-item {
    grid-template-columns: auto 1fr;
  }

  .cta-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .cta-actions .btn-primary,
  .cta-actions .btn-ghost,
  .cta-actions .btn-ghost-ink {
    width: 100%;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .dl-modal {
    padding: 1rem;
    align-items: end;
  }

  .dl-modal-panel {
    width: 100%;
    border-radius: 14px 14px 0 0;
    padding-bottom: calc(1.25rem + env(safe-area-inset-bottom, 0px));
  }
}

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

  .hero-media img,
  .reveal,
  .hero-copy {
    animation: none !important;
    transition: none !important;
    opacity: 1;
    transform: none;
  }
}