:root {
  --blue: #3f6fe8;
  --blue-dark: #2f57c4;
  --blue-soft: #eef3ff;
  --green: #2e9d4f;
  --amber: #b26a00;
  --red: #d64545;
  --ink: #1d2433;
  --ink-soft: #545e70;
  --line: #e2e7f0;
  --bg: #ffffff;
  --bg-alt: #f6f8fc;
  --radius: 16px;
  --max: 1080px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Pretendard", "Noto Sans KR", "Malgun Gothic", sans-serif;
  font-size: 17px;
  line-height: 1.7;
  word-break: keep-all;
  overflow-wrap: break-word;
}

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

a { color: var(--blue-dark); }

a:focus-visible, summary:focus-visible, .btn:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 3px;
  border-radius: 8px;
}

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

.skip {
  position: absolute; left: -9999px; top: 8px;
  background: var(--ink); color: #fff; padding: 8px 14px; border-radius: 8px; z-index: 10;
}
.skip:focus { left: 8px; }

/* header */
.site-header { border-bottom: 1px solid var(--line); background: #fff; }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 12px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--ink); text-decoration: none; font-size: 17px; }
.brand img { width: 32px; height: 32px; border-radius: 8px; }
.header-nav { display: flex; gap: 18px; font-size: 15px; }
.header-nav a { color: var(--ink-soft); text-decoration: none; }
.header-nav a:hover { color: var(--ink); }

/* buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 52px; padding: 0 26px; border-radius: 12px;
  background: var(--blue); color: #fff; font-weight: 700; font-size: 17px; text-decoration: none;
}
.btn:hover { background: var(--blue-dark); }

/* hero */
.hero { padding: 56px 0 48px; background: linear-gradient(180deg, var(--blue-soft) 0%, #fff 100%); }
.hero .wrap { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 48px; align-items: center; }
.hero h1 { font-size: 40px; line-height: 1.3; margin: 0 0 18px; letter-spacing: -0.02em; }
.hero .lead { font-size: 19px; color: var(--ink-soft); margin: 0 0 28px; }
.hero .note { font-size: 14px; color: var(--ink-soft); margin: 14px 0 0; }
.hero .app-name { display: inline-block; font-size: 15px; font-weight: 700; color: var(--blue-dark); background: #fff; border: 1px solid #cdd9fa; border-radius: 999px; padding: 4px 14px; margin-bottom: 18px; }
.hero figure { margin: 0; justify-self: center; }

.phone {
  width: 100%; max-width: 270px; border-radius: 28px; border: 8px solid #1d2433;
  box-shadow: 0 18px 40px rgba(29, 36, 51, 0.18); background: #fff;
}

/* sections */
section { padding: 64px 0; }
section.alt { background: var(--bg-alt); }
h2 { font-size: 30px; line-height: 1.35; margin: 0 0 12px; letter-spacing: -0.01em; }
.section-lead { color: var(--ink-soft); margin: 0 0 36px; max-width: 720px; }
h3 { font-size: 20px; margin: 0 0 8px; line-height: 1.4; }

.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.card p { margin: 0; color: var(--ink-soft); }

/* steps */
.steps { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.steps li { display: flex; flex-direction: column; gap: 14px; }
.step-num { display: inline-flex; width: 30px; height: 30px; border-radius: 50%; background: var(--blue); color: #fff; font-weight: 700; font-size: 15px; align-items: center; justify-content: center; }
.steps .who { font-size: 14px; color: var(--blue-dark); font-weight: 700; }
.steps p { margin: 0; color: var(--ink-soft); font-size: 16px; }
.steps img { border-radius: 18px; border: 1px solid var(--line); }

/* levels */
.levels { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px 20px; }
.levels details { background: #fff; border: 1px solid var(--line); border-radius: 12px; }
.levels summary { cursor: pointer; padding: 14px 44px 14px 18px; display: flex; gap: 12px; align-items: baseline; list-style: none; position: relative; }
.levels summary::-webkit-details-marker { display: none; }
.levels summary::after { content: "+"; position: absolute; right: 18px; top: 14px; color: var(--ink-soft); font-weight: 700; }
.levels details[open] summary::after { content: "−"; }
.lv { font-weight: 800; color: var(--blue-dark); min-width: 46px; }
.age { font-weight: 700; min-width: 58px; }
.topic { color: var(--ink-soft); }
.levels ul { margin: 0; padding: 0 18px 16px 40px; color: var(--ink-soft); font-size: 16px; }

/* weakness */
.badges { display: flex; flex-wrap: wrap; gap: 12px; margin: 0; padding: 0; list-style: none; }
.badges li { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 14px 18px; font-size: 16px; }
.badges strong { margin-right: 6px; }
.good { color: var(--green); }
.mid { color: var(--amber); }
.weak { color: var(--red); }

/* pricing */
.plans { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.plan { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.plan.featured { border: 2px solid var(--blue); }
.plan .count { font-size: 30px; font-weight: 800; margin: 6px 0 4px; }
.plan .count small { font-size: 16px; font-weight: 600; color: var(--ink-soft); }
.plan ul { margin: 12px 0 0; padding-left: 20px; color: var(--ink-soft); font-size: 16px; }
.fineprint { font-size: 15px; color: var(--ink-soft); margin-top: 20px; }

/* faq */
.faq { max-width: 820px; }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; padding: 18px 32px 18px 0; font-weight: 700; position: relative; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 4px; top: 18px; color: var(--ink-soft); }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin: 0 0 18px; color: var(--ink-soft); }

/* cta + footer */
.cta { text-align: center; }
.cta p { color: var(--ink-soft); margin: 0 0 24px; }
.site-footer { border-top: 1px solid var(--line); padding: 32px 0 40px; font-size: 14px; color: var(--ink-soft); }
.site-footer .links { display: flex; flex-wrap: wrap; gap: 8px 20px; margin: 0 0 12px; padding: 0; list-style: none; }
.site-footer p { margin: 4px 0; }

/* 404 */
.notfound { min-height: 60vh; display: flex; align-items: center; text-align: center; }
.notfound .wrap { width: 100%; }

@media (max-width: 900px) {
  .hero .wrap { grid-template-columns: 1fr; gap: 36px; }
  .hero h1 { font-size: 32px; }
  .cards, .plans { grid-template-columns: 1fr; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .levels { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  body { font-size: 16px; }
  section { padding: 48px 0; }
  .hero { padding: 40px 0 36px; }
  .hero h1 { font-size: 28px; }
  .hero .lead { font-size: 17px; }
  h2 { font-size: 25px; }
  .header-nav { display: none; }
  .btn { width: 100%; }
  .steps { gap: 28px 16px; }
  .levels summary { flex-wrap: wrap; gap: 4px 12px; }
  .topic { width: 100%; }
}