:root {
  --blue: #1759d7;
  --blue-deep: #0d3ea6;
  --sky: #eaf3ff;
  --orange: #ff8a00;
  --pink: #ff5d7d;
  --green: #25a86b;
  --ink: #13203a;
  --muted: #60708d;
  --line: #dfe8f7;
  --surface: #ffffff;
  --page: #f4f8ff;
  --shadow: 0 18px 50px rgba(35, 82, 151, 0.11);
  --radius: 26px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 4%, rgba(105, 183, 255, 0.2), transparent 26rem),
    radial-gradient(circle at 92% 14%, rgba(255, 174, 66, 0.13), transparent 22rem),
    var(--page);
  font-family: Inter, ui-rounded, "SF Pro Rounded", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.58;
  -webkit-font-smoothing: antialiased;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

a {
  color: inherit;
}

img {
  max-width: 100%;
  height: auto;
}

.reading-progress {
  position: fixed;
  inset: 0 0 auto;
  z-index: 50;
  height: 4px;
  background: rgba(255, 255, 255, 0.74);
}

.reading-progress span {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--orange), var(--pink), var(--blue));
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  width: min(100% - 32px, 980px);
  margin: 18px auto 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  border-radius: 18px;
}

.brand img {
  display: block;
  width: 226px;
  border-radius: 15px;
}

.home-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 17px;
  border: 1px solid rgba(23, 89, 215, 0.16);
  border-radius: 14px;
  color: var(--blue-deep);
  background: rgba(255, 255, 255, 0.72);
  font-size: 14px;
  font-weight: 750;
  text-decoration: none;
}

main {
  width: min(100% - 32px, 820px);
  margin: 24px auto 0;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: clamp(30px, 7vw, 58px);
  border: 1px solid rgba(23, 89, 215, 0.1);
  border-radius: 34px;
  background:
    linear-gradient(135deg, rgba(255,255,255,0.98), rgba(234,243,255,0.92)),
    var(--surface);
  box-shadow: var(--shadow);
}

.hero::after {
  content: "";
  position: absolute;
  top: -78px;
  right: -82px;
  width: 220px;
  aspect-ratio: 1;
  border-radius: 50%;
  background: linear-gradient(140deg, rgba(69, 151, 255, 0.24), rgba(255, 153, 0, 0.16));
  filter: blur(2px);
}

.eyebrow,
.section-kicker {
  margin: 0;
  color: var(--blue);
  font-size: 13px;
  font-weight: 850;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

h1,
h2,
h3,
h4,
p {
  text-wrap: pretty;
}

h1 {
  position: relative;
  z-index: 1;
  max-width: 650px;
  margin: 10px 0 16px;
  font-size: clamp(34px, 7.2vw, 58px);
  line-height: 1.04;
  letter-spacing: -0.045em;
}

.hero > p {
  max-width: 640px;
  margin: 0;
  color: var(--muted);
  font-size: clamp(17px, 3vw, 20px);
}

.hero-note {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-top: 26px;
  padding: 16px 18px;
  border: 1px solid rgba(37, 168, 107, 0.16);
  border-radius: 18px;
  background: rgba(236, 255, 247, 0.78);
  font-size: 15px;
}

.hero-note__icon {
  display: grid;
  flex: 0 0 27px;
  width: 27px;
  height: 27px;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: var(--green);
  font-weight: 900;
}

.toc {
  position: sticky;
  top: 10px;
  z-index: 20;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  margin: 18px 0 0;
  padding: 9px;
  border: 1px solid rgba(23, 89, 215, 0.12);
  border-radius: 19px;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: 0 10px 32px rgba(35, 82, 151, 0.09);
  backdrop-filter: blur(14px);
  scrollbar-width: none;
}

.toc::-webkit-scrollbar {
  display: none;
}

.toc a {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  min-height: 40px;
  padding: 0 14px;
  border-radius: 12px;
  color: #50617f;
  font-size: 14px;
  font-weight: 750;
  text-decoration: none;
}

.toc a:hover,
.toc a:focus-visible,
.toc a[aria-current="true"] {
  color: #fff;
  background: var(--blue);
  outline: none;
}

.section {
  padding-top: 72px;
}

.section-heading {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 22px;
}

.section-number {
  display: grid;
  flex: 0 0 48px;
  width: 48px;
  height: 48px;
  place-items: center;
  border-radius: 15px;
  color: #fff;
  background: linear-gradient(145deg, var(--orange), #ff6e3a);
  box-shadow: 0 9px 22px rgba(255, 122, 31, 0.23);
  font-size: 14px;
  font-weight: 900;
}

.section-heading h2,
.support h2 {
  margin: 3px 0 0;
  font-size: clamp(28px, 5vw, 40px);
  line-height: 1.12;
  letter-spacing: -0.035em;
}

.card {
  margin-top: 15px;
  padding: clamp(22px, 5vw, 34px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 0 12px 38px rgba(35, 82, 151, 0.07);
}

.card--accent {
  border-color: rgba(23, 89, 215, 0.18);
  background:
    linear-gradient(180deg, rgba(234, 243, 255, 0.66), #fff 42%),
    #fff;
}

.card h3,
.step h3 {
  margin: 0 0 10px;
  font-size: clamp(20px, 3.6vw, 24px);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.card h4 {
  margin: 28px 0 8px;
  font-size: 18px;
}

.card p,
.step p,
.details-content p {
  margin: 0;
}

.card p + p,
.details-content p + p {
  margin-top: 12px;
}

.card-title-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 10px;
}

.card-title-row h3 {
  margin: 0;
}

.card-icon {
  display: grid;
  flex: 0 0 50px;
  width: 50px;
  height: 50px;
  place-items: center;
  border-radius: 15px;
  color: #fff;
  background: var(--blue);
  font-size: 12px;
  font-weight: 900;
}

.check-list,
.plain-list,
.card ol,
.details-content ol,
.large-list {
  margin: 16px 0 0;
  padding-left: 1.3em;
}

.check-list {
  list-style: none;
  padding: 0;
}

.check-list li {
  position: relative;
  padding: 6px 0 6px 35px;
}

.check-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 6px;
  display: grid;
  width: 24px;
  height: 24px;
  place-items: center;
  border-radius: 8px;
  color: var(--green);
  background: #e7f9f1;
  font-size: 13px;
  font-weight: 900;
}

.plain-list li,
.card ol li,
.details-content ol li,
.large-list li {
  padding: 4px 0 4px 4px;
}

.muted {
  margin-top: 16px !important;
  color: var(--muted);
  font-size: 15px;
}

.warning,
.tip,
.legal-note {
  margin-top: 20px;
  padding: 15px 17px;
  border-radius: 16px;
}

.warning {
  border-left: 4px solid var(--orange);
  background: #fff7e9;
}

.warning--compact {
  font-size: 15px;
}

.tip {
  border-left: 4px solid var(--blue);
  background: var(--sky);
}

.legal-note {
  border-left: 4px solid #8b5cf6;
  background: #f4f0ff;
  color: #4e3a78;
  font-size: 15px;
}

.specs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin: 18px 0;
}

.specs div {
  padding: 15px 10px;
  border-radius: 15px;
  background: var(--sky);
  text-align: center;
}

.specs strong,
.specs span {
  display: block;
}

.specs strong {
  color: var(--blue-deep);
  font-size: 19px;
}

.specs span {
  margin-top: 2px;
  color: var(--muted);
  font-size: 12px;
}

.steps {
  margin: 0;
  padding: 0;
  list-style: none;
}

.step {
  position: relative;
  display: grid;
  grid-template-columns: 50px 1fr;
  gap: 14px;
  padding: 0 0 28px;
}

.step:not(:last-child)::before {
  content: "";
  position: absolute;
  top: 50px;
  bottom: 4px;
  left: 24px;
  width: 2px;
  background: linear-gradient(var(--line), rgba(223, 232, 247, 0.25));
}

.step > div {
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: 21px;
  background: #fff;
  box-shadow: 0 10px 32px rgba(35, 82, 151, 0.06);
}

.step__number {
  position: relative;
  z-index: 1;
  display: grid;
  width: 50px;
  height: 50px;
  place-items: center;
  border: 5px solid var(--page);
  border-radius: 50%;
  color: #fff;
  background: var(--blue);
  font-weight: 900;
}

.app-link {
  display: grid;
  grid-template-columns: 44px 1fr auto;
  align-items: center;
  gap: 12px;
  min-height: 66px;
  margin-top: 16px;
  padding: 10px 14px;
  border: 1px solid #dfe7f3;
  border-radius: 17px;
  background: #f8fbff;
  color: var(--ink);
  text-decoration: none;
}

.app-link img {
  border-radius: 12px;
}

.app-link strong,
.app-link small {
  display: block;
}

.app-link small {
  color: var(--muted);
}

.app-link > span:last-child {
  color: var(--blue);
  font-size: 22px;
}

.image-button {
  display: block;
  width: 100%;
  margin-top: 16px;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 17px;
  color: var(--muted);
  background: #f9fbff;
  cursor: zoom-in;
  font: inherit;
  text-align: center;
}

.image-button img {
  display: block;
  width: 100%;
  border-radius: 11px;
}

.image-button span {
  display: block;
  padding: 8px 4px 1px;
  font-size: 13px;
  font-weight: 700;
}

.image-button--small img {
  width: min(100%, 286px);
  margin: 0 auto;
}

.image-button--portrait {
  width: min(100%, 460px);
  margin-inline: auto;
}

.two-column {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 15px;
}

.two-column .card {
  margin-top: 0;
}

.faq-list {
  display: grid;
  gap: 11px;
}

details {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: #fff;
  box-shadow: 0 9px 28px rgba(35, 82, 151, 0.05);
}

summary {
  position: relative;
  padding: 20px 58px 20px 20px;
  cursor: pointer;
  font-size: 18px;
  font-weight: 800;
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

summary::after {
  content: "+";
  position: absolute;
  top: 50%;
  right: 18px;
  display: grid;
  width: 30px;
  height: 30px;
  place-items: center;
  border-radius: 10px;
  color: var(--blue);
  background: var(--sky);
  transform: translateY(-50%);
  transition: transform 0.2s ease;
}

details[open] summary::after {
  transform: translateY(-50%) rotate(45deg);
}

.details-content {
  padding: 0 20px 22px;
  color: #2d3a52;
}

.image-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 18px;
}

.image-grid .image-button {
  margin-top: 0;
}

.large-list {
  margin-top: 0;
}

.large-list li + li {
  margin-top: 14px;
}

.memo-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.image-button--memo {
  margin-top: 0;
  padding: 9px;
  background: #fff;
  box-shadow: 0 10px 32px rgba(35, 82, 151, 0.07);
}

.support {
  margin-top: 76px;
  padding: clamp(28px, 7vw, 52px);
  border-radius: 32px;
  color: #fff;
  background:
    radial-gradient(circle at 100% 0, rgba(255, 174, 66, 0.32), transparent 20rem),
    linear-gradient(145deg, #0d3ea6, #1767e8);
  box-shadow: 0 24px 54px rgba(23, 89, 215, 0.22);
}

.support .section-kicker {
  color: #b9d6ff;
}

.support > p:not(.section-kicker) {
  margin: 12px 0 0;
  color: #d9e8ff;
}

.support-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 24px;
}

.support-actions a {
  display: grid;
  grid-template-columns: 46px 1fr auto;
  align-items: center;
  gap: 12px;
  min-height: 78px;
  padding: 12px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 18px;
  color: var(--ink);
  background: #fff;
  text-decoration: none;
}

.support-actions img {
  border-radius: 14px;
}

.support-actions strong,
.support-actions small {
  display: block;
}

.support-actions small {
  color: var(--muted);
}

.support-actions a > span:last-child {
  color: var(--blue);
  font-size: 22px;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: min(100% - 32px, 820px);
  margin: 22px auto 0;
  padding: 18px 0 max(26px, env(safe-area-inset-bottom));
  color: var(--muted);
  font-size: 14px;
}

.to-top {
  min-height: 44px;
  padding: 0 15px;
  border: 1px solid var(--line);
  border-radius: 13px;
  color: var(--blue-deep);
  background: #fff;
  cursor: pointer;
  font: inherit;
  font-weight: 800;
}

.lightbox {
  width: min(96vw, 980px);
  max-width: none;
  max-height: 94dvh;
  margin: auto;
  padding: 54px 10px 10px;
  border: 0;
  border-radius: 22px;
  background: #0d1422;
  box-shadow: 0 30px 90px rgba(0, 0, 0, 0.5);
}

.lightbox::backdrop {
  background: rgba(5, 11, 23, 0.78);
  backdrop-filter: blur(6px);
}

.lightbox img {
  display: block;
  max-height: calc(94dvh - 66px);
  margin: 0 auto;
  border-radius: 13px;
  object-fit: contain;
}

.lightbox__close {
  position: absolute;
  top: 9px;
  right: 10px;
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 0;
  border-radius: 12px;
  color: #fff;
  background: rgba(255,255,255,0.13);
  cursor: pointer;
  font: inherit;
  font-size: 28px;
}

:focus-visible {
  outline: 3px solid rgba(255, 138, 0, 0.75);
  outline-offset: 3px;
}

@media (hover: hover) {
  .home-link,
  .toc a,
  .app-link,
  .support-actions a,
  .image-button,
  .to-top {
    transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease;
  }

  .home-link:hover,
  .app-link:hover,
  .support-actions a:hover,
  .image-button:hover,
  .to-top:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 28px rgba(35, 82, 151, 0.13);
  }
}

@media (max-width: 640px) {
  body {
    font-size: 16px;
  }

  .site-header,
  main,
  .site-footer {
    width: min(100% - 22px, 820px);
  }

  .site-header {
    margin-top: 12px;
  }

  .brand img {
    width: 176px;
  }

  .home-link {
    min-height: 40px;
    padding: 0 12px;
    font-size: 13px;
  }

  main {
    margin-top: 15px;
  }

  .hero {
    padding: 27px 21px;
    border-radius: 27px;
  }

  .hero-note {
    padding: 14px;
  }

  .toc {
    top: 7px;
    margin-inline: -2px;
  }

  .section {
    padding-top: 56px;
  }

  .section-heading {
    gap: 12px;
  }

  .section-number {
    flex-basis: 43px;
    width: 43px;
    height: 43px;
    border-radius: 13px;
  }

  .card {
    padding: 20px 17px;
    border-radius: 21px;
  }

  .specs {
    gap: 7px;
  }

  .specs div {
    padding: 12px 6px;
  }

  .specs strong {
    font-size: 17px;
  }

  .step {
    grid-template-columns: 40px 1fr;
    gap: 9px;
  }

  .step__number {
    width: 40px;
    height: 40px;
    border-width: 4px;
  }

  .step:not(:last-child)::before {
    top: 40px;
    left: 19px;
  }

  .step > div {
    padding: 17px 14px;
    border-radius: 18px;
  }

  .two-column,
  .support-actions,
  .memo-grid {
    grid-template-columns: 1fr;
  }

  .image-grid {
    gap: 8px;
  }

  summary {
    padding: 18px 54px 18px 17px;
    font-size: 16px;
  }

  .details-content {
    padding: 0 17px 19px;
  }

  .support {
    margin-top: 58px;
    padding: 28px 18px;
    border-radius: 27px;
  }
}

@media (max-width: 380px) {
  .brand img {
    width: 156px;
  }

  .home-link {
    padding-inline: 10px;
  }

  .specs {
    grid-template-columns: 1fr;
  }

  .specs div {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
    padding-inline: 14px;
  }

  .image-grid {
    grid-template-columns: 1fr;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}