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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--body);
  font-family:'PingFang SC','Microsoft YaHei','Noto Sans SC',-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

p,
h1,
h2,
h3,
dl,
dd,
ul,
ol {
  margin: 0;
}

ul,
ol {
  padding: 0;
  list-style: none;
}

button,
summary,
select {
  font: inherit;
  color: inherit;
}

.container {
  width: min(var(--container), calc(100% - 48px));
  margin-inline: auto;
}

.skip-link {
  position: fixed;
  top: -60px;
  left: 16px;
  z-index: 100;
  padding: 10px 16px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 13px;
  transition: top .2s ease;
}

.skip-link:focus {
  top: 12px;
}

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--navy);
  color: #fff;
  height: 66px;
  transition: box-shadow .2s ease;
}

.site-header.is-scrolled {
  box-shadow: 0 8px 24px -18px rgba(0, 0, 0, .8);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 66px;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(145deg, #2f8ac9, #0d4f78);
  color: #d9f1ff;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .18);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-text strong {
  font-size: 17px;
  letter-spacing: .04em;
  font-weight: 700;
}

.brand-text small {
  margin-top: 2px;
  color: #8fc6e8;
  font-size: 8px;
  letter-spacing: .18em;
  font-weight: 600;
}

.site-nav {
  display: flex;
  align-items: center;
  margin-left: auto;
  min-width: 0;
}
.site-nav > ul { display: flex; align-items: center; gap: 22px; }
.site-nav li { position: relative; }
.site-nav .nav-drop {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 176px;
  max-height: 360px;
  overflow-y: auto;
  padding: 6px;
  background: #0c2b40;
  border: 1px solid rgba(255, 255, 255, .16);
  border-radius: 10px;
  box-shadow: 0 18px 38px -18px rgba(0, 0, 0, .8);
  z-index: 60;
  white-space: normal;
}
.site-nav li:hover > .nav-drop { display: block; }
.site-nav .nav-drop a { display: block; padding: 6px 10px; border-radius: 6px; font-size: 12.5px; color: #d8e8f2; white-space: normal; }
.site-nav .nav-drop a::after { display: none; }
.site-nav .nav-drop a:hover { background: rgba(93, 182, 234, .16); color: #fff; }
.site-nav .nav-all > a { color: #fff; font-weight: 600; }

.site-nav a {
  position: relative;
  font-size: 13.5px;
  color: #d8e8f2;
  white-space: nowrap;
  padding: 6px 0;
  transition: color .18s ease;
}

.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  border-radius: 2px;
  background: #5db6ea;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .18s ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a[aria-current="page"] {
  color: #fff;
}

.site-nav a:hover::after,
.site-nav a:focus-visible::after,
.site-nav a[aria-current="page"]::after {
  transform: scaleX(1);
}

.site-nav .nav-quick {
  padding: 8px 16px;
  border-radius: var(--pill);
  background: var(--accent);
  color: #fff;
  font-size: 12.5px;
  font-weight: 600;
}

.site-nav .nav-quick::after { display: none; }

.site-nav .nav-quick:hover {
  background: var(--accent-bright);
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(255, 255, 255, .22);
  border-radius: 10px;
  background: transparent;
  color: #fff;
  cursor: pointer;
}

/* ---------- shared ---------- */
.kicker {
  color: var(--accent);
  font-family:'PingFang SC','Microsoft YaHei','Noto Sans SC',-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .2em;
  text-transform: uppercase;
}

.section-head {
  margin-bottom: 12px;
}

.section-head h2,
.water h2,
.compare h2,
.faq h2 {
  margin-top: 4px;
  color: var(--ink);
  font-size: 24px;
  line-height: 1.25;
  font-weight: 800;
  letter-spacing: -.02em;
}

.section-sub {
  margin-top: 5px;
  color: var(--muted);
  font-size: 12.5px;
  line-height: 1.7;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0 20px;
  border-radius: var(--pill);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .01em;
  transition: background .18s ease, transform .18s ease, border-color .18s ease;
}

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

.btn-primary {
  background: #fff;
  color: var(--accent-deep);
}

.btn-primary:hover { background: #d9f0ff; }

.btn-ghost {
  border: 1px solid rgba(255, 255, 255, .36);
  color: #fff;
}

.btn-ghost:hover { border-color: rgba(255, 255, 255, .7); background: rgba(255, 255, 255, .07); }

:where(a, button, summary, select):focus-visible {
  outline: 2px solid #7cc4f0;
  outline-offset: 2px;
}

/* ---------- hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  height: 340px;
  background: linear-gradient(100deg, var(--hero-1) 0%, var(--hero-2) 48%, var(--hero-3) 100%);
  color: #fff;
  isolation: isolate;
}

.hero-media {
  position: absolute;
  inset: 0 0 0 auto;
  width: min(58%, 1000px);
  z-index: -1;
}

.hero-media::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, var(--hero-1) 0%, rgba(13, 74, 94, .94) 16%, rgba(6, 47, 69, .38) 48%, rgba(4, 31, 49, .12) 78%),
    linear-gradient(0deg, rgba(4, 31, 49, .55) 0%, transparent 40%);
}

.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 46%;
}

.hero-inner {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  height: 100%;
  padding-block: 24px;
}

.eyebrow {
  color: #8fd0f5;
  font-family:'PingFang SC','Microsoft YaHei','Noto Sans SC',-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: .16em;
}

.hero h1 {
  margin-top: 8px;
  max-width: 560px;
  font-size: 40px;
  line-height: 1.16;
  font-weight: 800;
  letter-spacing: -.03em;
  color: #fff;
  text-shadow: 0 2px 18px rgba(0, 0, 0, .18);
}

.hero-lead {
  margin-top: 10px;
  max-width: 540px;
  color: #d1e6f1;
  font-size: 13.5px;
  line-height: 1.72;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.hero-stats {
  display: flex;
  gap: 34px;
  margin-top: 18px;
}

.stat dt {
  color: #fff;
  font-family:'PingFang SC','Microsoft YaHei','Noto Sans SC',-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;
  font-size: 20px;
  font-weight: 700;
  line-height: 1.1;
  white-space: nowrap;
}

.stat dd {
  margin-top: 3px;
  color: #9ec4d8;
  font-size: 11.5px;
  letter-spacing: .04em;
}

.hero-note {
  margin-top: 12px;
  color: #86aabd;
  font-size: 10.5px;
  line-height: 1.5;
}

/* ---------- topics ---------- */
.topics {
  padding: 16px 0 16px;
  background: linear-gradient(180deg, #eef4f9 0%, var(--bg) 100%);
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.topic-card {
  display: block;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform .2s ease, border-color .2s ease, box-shadow .2s ease;
}

.topic-card:hover,
.topic-card:focus-visible {
  transform: translateY(-3px);
  border-color: #bcd9ec;
  box-shadow: 0 20px 34px -26px rgba(6, 44, 68, .55);
}

.topic-media {
  display: block;
  height: 60px;
  overflow: hidden;
  background: #d7e6f0;
}

.topic-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .35s ease;
}

.topic-card:hover .topic-media img { transform: scale(1.04); }

.topic-body {
  display: block;
  padding: 6px 13px 8px;
}

.topic-title-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.topic-num {
  display: inline-grid;
  place-items: center;
  width: 23px;
  height: 23px;
  flex: none;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-family:'PingFang SC','Microsoft YaHei','Noto Sans SC',-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;
  font-size: 10px;
  font-weight: 700;
}

.topic-name {
  color: var(--ink);
  font-size: 14.5px;
  font-weight: 700;
}

.topic-desc {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-size: 11px;
  line-height: 1.4;
}

/* ---------- editor ---------- */
.editor {
  padding: 18px 0 22px;
}

.editor-inner {
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr);
  gap: 30px;
  align-items: start;
}

.editor-head h2 { margin-top: 4px; }

.pick-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.pick-card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform .2s ease, border-color .2s ease;
}

.pick-card:hover,
.pick-card:focus-visible {
  transform: translateY(-3px);
  border-color: #bcd9ec;
}

.pick-media {
  display: block;
  height: 88px;
  overflow: hidden;
  background: #d7e6f0;
}

.pick-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .35s ease;
}

.pick-card:hover .pick-media img { transform: scale(1.04); }

.pick-body {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 10px 13px 12px;
}

.pick-title {
  color: var(--ink);
  font-size: 13.5px;
  font-weight: 700;
  line-height: 1.42;
}

.pick-desc {
  color: var(--muted);
  font-size: 11.5px;
  line-height: 1.5;
}

.pick-meta {
  margin-top: 1px;
  color: var(--faint);
  font-size: 10.5px;
}

/* ---------- stages ---------- */
.stages {
  padding: 16px 0 18px;
  background: linear-gradient(180deg, #edf4fa 0%, #f6f9fc 100%);
  border-block: 1px solid #e3edf5;
}

.stages-head .section-sub { max-width: 760px; }

.stage-track {
  position: relative;
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
  margin-top: 12px;
}

.stage-track::before {
  content: "";
  position: absolute;
  top: 20px;
  left: 6%;
  right: 6%;
  height: 2px;
  background: linear-gradient(90deg, #bfe0f4, #8fc8e9, #bfe0f4);
}

.stage-item {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  z-index: 1;
}

.stage-dot {
  display: block;
  width: 40px;
  height: 40px;
  overflow: hidden;
  border: 3px solid #fff;
  border-radius: 50%;
  background: #cfe4f2;
  box-shadow: 0 4px 12px -6px rgba(6, 44, 68, .4);
}

.stage-dot img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.stage-num {
  margin-top: 4px;
  color: var(--accent);
  font-family:'PingFang SC','Microsoft YaHei','Noto Sans SC',-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;
  font-size: 10px;
  font-weight: 700;
}

.stage-name {
  margin-top: 1px;
  color: var(--ink);
  font-size: 13.5px;
  font-weight: 700;
}

.stage-days {
  margin-top: 1px;
  color: var(--body);
  font-size: 11px;
}

.stage-desc {
  margin-top: 3px;
  max-width: 178px;
  color: var(--muted);
  font-size: 10.5px;
  line-height: 1.42;
}

/* ---------- water + compare ---------- */
.water-compare {
  padding: 18px 0 20px;
}

.wc-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.06fr);
  gap: 34px;
  align-items: start;
}

.wc-grid > *,
.water,
.compare { min-width: 0; }

.table-wrap {
  margin-top: 10px;
  max-width: 100%;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 11.5px;
  line-height: 1.45;
  color: var(--body);
}

th,
td {
  padding: 7px 10px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid #edf3f8;
}

thead th {
  background: var(--accent-deep);
  color: #fff;
  font-weight: 600;
  white-space: nowrap;
}

tbody th {
  color: var(--ink);
  font-weight: 600;
  white-space: nowrap;
}

tbody tr:last-child th,
tbody tr:last-child td { border-bottom: 0; }

tbody tr:nth-child(even) { background: #f7fbfe; }

.param-table { min-width: 470px; }
.compare-table { min-width: 560px; }

.table-note {
  margin-top: 6px;
  color: var(--faint);
  font-size: 10.5px;
  line-height: 1.5;
}

/* ---------- faq ---------- */
.faq {
  padding: 36px 0 40px;
  background: linear-gradient(180deg, #f6f9fc 0%, #eef4f9 100%);
  border-block: 1px solid #e3edf5;
}

.faq-grid {
  display: grid;
  grid-template-columns: minmax(0, .8fr) minmax(0, 1.2fr);
  gap: 40px;
  align-items: start;
}

.precheck {
  margin-top: 14px;
  padding: 12px 14px;
  border: 1px solid #cfe4f2;
  border-radius: 12px;
  background: var(--surface);
}

.precheck-title {
  color: var(--ink);
  font-size: 12px;
  font-weight: 700;
}

.precheck ul {
  margin-top: 6px;
  display: grid;
  gap: 4px;
}

.precheck li {
  position: relative;
  padding-left: 15px;
  color: var(--muted);
  font-size: 11.5px;
  line-height: 1.5;
}

.precheck li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .55em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-bright);
}

.faq-list {
  display: grid;
  gap: 8px;
}

.faq-item {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  transition: border-color .18s ease;
}

.faq-item[open] { border-color: #b9d8ec; }

.faq-item summary {
  position: relative;
  padding: 12px 42px 12px 14px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 600;
  line-height: 1.5;
  cursor: pointer;
  list-style: none;
}

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

.faq-item summary::after {
  content: "";
  position: absolute;
  right: 15px;
  top: 50%;
  width: 8px;
  height: 8px;
  border-right: 1.6px solid var(--accent);
  border-bottom: 1.6px solid var(--accent);
  transform: translateY(-70%) rotate(45deg);
  transition: transform .2s ease;
}

.faq-item[open] summary::after {
  transform: translateY(-30%) rotate(225deg);
}

.faq-item p {
  padding: 0 14px 12px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.7;
}

/* ---------- notice ---------- */
.notice {
  padding: 18px 0;
  background: #f8fbfd;
}

.notice-inner {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 12px 16px;
  border: 1px solid #cfe6f5;
  border-radius: 10px;
  background: #eaf6fd;
}

.notice-icon {
  flex: none;
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: #d3edfc;
  color: var(--accent);
}

.notice p {
  color: #3c6a84;
  font-size: 11.5px;
  line-height: 1.65;
}

.notice strong {
  color: var(--ink);
  font-weight: 700;
}

/* ---------- footer ---------- */
.site-footer {
  background: var(--footer);
  color: #d7e7f2;
  padding: 24px 0 16px;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: 30px;
}
.footer-col { flex: 1 1 190px; min-width: 160px; }
.footer-brand { flex: 1 1 240px; }
.footer-icp { display: block; color: #8fb3c8; font-size: 11px; line-height: 1.8; }

.footer-title {
  color: #fff;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .03em;
}

.footer-tagline {
  margin-top: 6px;
  max-width: 300px;
  color: #a9c6d8;
  font-size: 11.5px;
  line-height: 1.65;
}

.footer-label {
  margin-bottom: 7px;
  color: #7fb6d4;
  font-family:'PingFang SC','Microsoft YaHei','Noto Sans SC',-apple-system,BlinkMacSystemFont,'Segoe UI',Arial,sans-serif;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .14em;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px 14px;
}

.footer-links .footer-label { grid-column: 1 / -1; }

.footer-links a {
  color: #c9dfec;
  font-size: 11.5px;
  line-height: 1.8;
  transition: color .18s ease;
}

.footer-links a:hover,
.footer-links a:focus-visible { color: #fff; }

.footer-principles p {
  color: #a9c6d8;
  font-size: 11.5px;
  line-height: 1.8;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: 14px;
  padding-top: 10px;
  border-top: 1px solid rgba(255, 255, 255, .12);
}

.footer-bottom p {
  color: #8fb3c8;
  font-size: 10.5px;
}

.to-top {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: #bcd9ec;
  font-size: 11px;
}

.to-top:hover { color: #fff; }

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .header-inner { gap: 14px; }
  .site-nav { margin-left: 0; flex: 1; min-width: 0; overflow-x: auto; scrollbar-width: none; -webkit-overflow-scrolling: touch; }
  .site-nav::-webkit-scrollbar { display: none; }
  .site-nav > ul { gap: 14px; padding-right: 10px; }
  .site-nav a { font-size: 12.5px; padding: 6px 0; }
  .site-nav a::after { display: none; }
  .site-nav .nav-drop { display: none !important; }
  .nav-toggle { display: none; }

  .hero-media { width: 64%; }

  .hero h1 { font-size: 36px; }

  .editor-inner { grid-template-columns: 1fr; gap: 16px; }

  .editor-head { display: grid; gap: 2px; }
}

@media (max-width: 980px) {
  .topic-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .pick-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .wc-grid { grid-template-columns: 1fr; gap: 26px; }
  .faq-grid { grid-template-columns: 1fr; gap: 22px; }
  .footer-inner { flex-direction: column; gap: 20px; }
  .footer-brand, .footer-col { flex: 0 0 auto; width: 100%; min-width: 0; }
}

@media (max-width: 760px) {
  .container { width: min(var(--container), calc(100% - 32px)); }
  .hero { height: auto; min-height: 430px; }
  .hero-media { width: 100%; }
  .hero-media::after {
    background:
      linear-gradient(90deg, rgba(6, 47, 69, .96) 0%, rgba(6, 47, 69, .82) 46%, rgba(4, 31, 49, .44) 100%),
      linear-gradient(0deg, rgba(4, 31, 49, .8) 0%, transparent 55%);
  }
  .hero-inner { padding-block: 34px; }
  .hero h1 { font-size: 30px; max-width: 420px; }
  .hero-lead { font-size: 13px; max-width: 420px; }
  .hero-stats { gap: 22px; }
  .stat dt { font-size: 18px; }
  .section-head h2,
  .water h2,
  .compare h2,
  .faq h2 { font-size: 22px; }
  .topic-media { height: 118px; }
  .pick-grid { grid-template-columns: 1fr; }
  .pick-media { height: 150px; }
  .stage-track { grid-template-columns: 1fr; gap: 14px; }
  .stage-track::before { display: none; }
  .stage-item {
    display: grid;
    grid-template-columns: 44px 1fr;
    grid-template-areas:
      "dot num"
      "dot name"
      "dot days"
      "dot desc";
    align-items: center;
    justify-items: start;
    text-align: left;
    column-gap: 12px;
    padding: 12px;
    border: 1px solid var(--line);
    border-radius: 12px;
    background: #fff;
  }
  .stage-dot { grid-area: dot; align-self: start; }
  .stage-num { grid-area: num; margin-top: 0; }
  .stage-name { grid-area: name; margin-top: 0; }
  .stage-days { grid-area: days; }
  .stage-desc { grid-area: desc; max-width: none; }
  .footer-inner { grid-template-columns: 1fr; gap: 20px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; gap: 8px; }
}

@media (max-width: 640px) {
  .topic-grid { grid-template-columns: 1fr; }
  .topic-media { height: 150px; }
  .hero-stats { flex-wrap: wrap; gap: 14px 24px; }
  .hero h1 { font-size: 27px; }
  .param-table { min-width: 440px; }
  .compare-table { min-width: 540px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}