:root {
  --bg: #f3f6f8;
  --ink: #16202c;
  --ink-2: #334155;
  --muted: #64748b;
  --line: #d7dee8;
  --surface: #ffffff;
  --soft: #e9f1f7;
  --accent: #2563eb;
  --accent-2: #0f766e;
  --accent-dark: #173c75;
  --shadow: 0 24px 70px rgba(15, 23, 42, 0.14);
  font-family: Arial, "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  letter-spacing: 0;
}

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  padding: 16px clamp(18px, 5vw, 72px);
  border-bottom: 1px solid rgba(215, 222, 232, 0.82);
  background: rgba(243, 246, 248, 0.9);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: max-content;
  font-size: 17px;
  font-weight: 900;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 7px;
  background: var(--ink);
  color: #fff;
  font-size: 17px;
  font-weight: 900;
}

.nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2.2vw, 26px);
  color: var(--muted);
  font-size: 14px;
  font-weight: 800;
  white-space: nowrap;
}

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

.nav-cta {
  padding: 10px 14px;
  border-radius: 7px;
  background: var(--ink);
  color: #fff !important;
}

.hero {
  position: relative;
  display: grid;
  align-items: end;
  min-height: calc(100vh - 63px);
  padding: clamp(90px, 13vw, 150px) clamp(20px, 6vw, 90px) clamp(56px, 8vw, 92px);
  overflow: hidden;
  background-image: url("./assets/studio-phi-ai-bpo-cover.png");
  background-position: center;
  background-size: cover;
}

.hero::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 94px;
  background: linear-gradient(180deg, rgba(243, 246, 248, 0), var(--bg));
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(10, 18, 32, 0.9) 0%, rgba(10, 18, 32, 0.72) 43%, rgba(10, 18, 32, 0.2) 100%),
    linear-gradient(180deg, rgba(10, 18, 32, 0.12), rgba(10, 18, 32, 0.54));
}

.hero-copy {
  position: relative;
  z-index: 2;
  max-width: 860px;
  color: #fff;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero .eyebrow {
  color: #c7d9ff;
}

.hero h1,
.section-head h2,
.case-copy h2,
.contact-section h2 {
  margin: 0;
  font-size: clamp(36px, 5.4vw, 72px);
  line-height: 1.08;
  letter-spacing: 0;
}

.hero-copy > p:not(.eyebrow),
.section-head > p:not(.eyebrow),
.case-copy > p,
.contact-section p:not(.eyebrow) {
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.9;
  font-weight: 600;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 760px;
  color: rgba(255, 255, 255, 0.86);
  font-size: 18px;
}

.hero-actions,
.contact-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0 20px;
  border-radius: 7px;
  font-size: 15px;
  font-weight: 900;
}

.button.primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 14px 32px rgba(37, 99, 235, 0.28);
}

.button.secondary {
  border: 1px solid rgba(255, 255, 255, 0.52);
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

.problem-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin: -36px clamp(20px, 6vw, 90px) 0;
  position: relative;
  z-index: 4;
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.problem-strip p {
  min-height: 112px;
  margin: 0;
  padding: 24px;
  border-right: 1px solid var(--line);
  color: var(--ink-2);
  font-size: 16px;
  font-weight: 900;
  line-height: 1.6;
}

.problem-strip p:last-child {
  border-right: 0;
}

.section {
  padding: 100px clamp(20px, 6vw, 90px);
}

.split-section,
.case-section,
.contact-section {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(430px, 1fr);
  gap: clamp(36px, 6vw, 78px);
  align-items: start;
}

.section-head {
  max-width: 840px;
}

.sticky-copy {
  position: sticky;
  top: 104px;
}

.service-steps,
.reason-grid,
.plan-grid {
  display: grid;
  gap: 16px;
}

.service-steps article,
.capability-grid article,
.reason-grid article,
.plan-grid article {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.service-steps article {
  min-height: 214px;
  padding: 28px;
}

.service-steps span,
.capability-grid span,
.flow-list span {
  display: block;
  margin-bottom: 28px;
  color: var(--accent);
  font-weight: 900;
}

h3 {
  margin: 0;
  font-size: 21px;
  line-height: 1.35;
  letter-spacing: 0;
}

article p,
.flow-list p,
.plan-grid li,
.result-list li,
.note {
  color: var(--muted);
  line-height: 1.75;
}

article p {
  margin: 16px 0 0;
}

.capability-section {
  background: #fff;
}

.capability-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 42px;
}

.capability-grid article {
  min-height: 238px;
  padding: 26px;
  background: #fbfdff;
}

.case-section {
  align-items: center;
  background: var(--soft);
}

.case-copy h2,
.contact-section h2 {
  font-size: clamp(34px, 4.4vw, 58px);
}

.result-list {
  display: grid;
  gap: 12px;
  padding: 0;
  margin: 28px 0 0;
  list-style: none;
}

.result-list li {
  position: relative;
  padding-left: 26px;
  color: var(--ink-2);
  font-weight: 800;
}

.result-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent-2);
}

.case-visual {
  margin: 0;
  border: 1px solid rgba(148, 163, 184, 0.45);
  border-radius: 8px;
  overflow: hidden;
  background: #fff;
  box-shadow: var(--shadow);
}

.reason-grid {
  grid-template-columns: repeat(4, 1fr);
  margin-top: 42px;
}

.reason-grid article {
  min-height: 250px;
  padding: 26px;
}

.flow-section {
  background: #fff;
}

.flow-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  padding: 0;
  margin: 42px 0 0;
  list-style: none;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.flow-list li {
  min-height: 270px;
  padding: 30px;
  border-right: 1px solid var(--line);
}

.flow-list li:last-child {
  border-right: 0;
}

.plan-section {
  background: #eef4f8;
}

.plan-grid {
  grid-template-columns: repeat(3, 1fr);
  margin-top: 42px;
  align-items: stretch;
}

.plan-grid article {
  padding: 28px;
}

.plan-grid .featured-plan {
  border-color: rgba(37, 99, 235, 0.5);
  box-shadow: 0 20px 60px rgba(37, 99, 235, 0.12);
}

.plan-name {
  margin: 0 0 18px;
  color: var(--accent);
  font-weight: 900;
}

.plan-grid ul {
  display: grid;
  gap: 10px;
  padding-left: 18px;
  margin: 22px 0 0;
}

.note {
  max-width: 980px;
  margin: 24px 0 0;
  font-size: 14px;
}

.contact-section {
  align-items: center;
  background: #121a27;
  color: #fff;
}

.contact-section .eyebrow {
  color: #9ebcff;
}

.contact-section p:not(.eyebrow) {
  color: #c1cad8;
}

.contact-actions {
  justify-content: flex-start;
  padding: 32px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.06);
}

@media (max-width: 1100px) {
  .split-section,
  .case-section,
  .contact-section {
    grid-template-columns: 1fr;
  }

  .sticky-copy {
    position: static;
  }

  .capability-grid,
  .reason-grid,
  .flow-list {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .problem-strip p:nth-child(2) {
    border-right: 0;
  }

  .problem-strip p:nth-child(-n + 2) {
    border-bottom: 1px solid var(--line);
  }
}

@media (max-width: 760px) {
  .site-header {
    align-items: flex-start;
    padding: 14px 16px;
  }

  .brand {
    font-size: 15px;
  }

  .nav {
    max-width: 100%;
    overflow-x: auto;
    padding-bottom: 4px;
    font-size: 13px;
  }

  .nav a:not(.nav-cta):nth-child(2) {
    display: none;
  }

  .hero {
    min-height: 720px;
    padding: 92px 18px 78px;
    background-position: center top;
  }

  .hero-overlay {
    background:
      linear-gradient(180deg, rgba(10, 18, 32, 0.78) 0%, rgba(10, 18, 32, 0.68) 55%, rgba(10, 18, 32, 0.82) 100%),
      linear-gradient(90deg, rgba(10, 18, 32, 0.6), rgba(10, 18, 32, 0.28));
  }

  .hero h1 {
    font-size: 40px;
  }

  .hero-copy > p:not(.eyebrow) {
    font-size: 16px;
  }

  .button {
    width: 100%;
  }

  .problem-strip {
    grid-template-columns: 1fr;
    margin: -28px 18px 0;
  }

  .problem-strip p {
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .problem-strip p:last-child {
    border-bottom: 0;
  }

  .section,
  .contact-section {
    padding: 78px 18px;
  }

  .section-head h2,
  .case-copy h2,
  .contact-section h2 {
    font-size: 35px;
  }

  .capability-grid,
  .reason-grid,
  .flow-list,
  .plan-grid {
    grid-template-columns: 1fr;
  }

  .flow-list li,
  .flow-list li:last-child {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .flow-list li:last-child {
    border-bottom: 0;
  }

  .contact-actions {
    padding: 22px;
  }
}