:root {
  --ink: #172334;
  --muted: #5f6d7c;
  --line: #dbe5ee;
  --paper: #ffffff;
  --soft: #f3f8fc;
  --blue: #1b74c8;
  --blue-dark: #0f4f8a;
  --cyan: #35b8cf;
  --shadow: 0 18px 48px rgba(27, 66, 105, .12);
  --radius: 22px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif; line-height: 1.75; }
a { color: var(--blue-dark); }
img { max-width: 100%; height: auto; }
.shell { width: min(1120px, calc(100% - 40px)); margin-inline: auto; }
.section { padding-block: 64px; }
.skip-link { position: fixed; z-index: 100; top: 8px; left: 8px; padding: 10px 16px; color: #fff; background: var(--ink); transform: translateY(-150%); }
.skip-link:focus { transform: none; }

.site-header { position: sticky; z-index: 20; top: 0; border-bottom: 1px solid rgba(219, 229, 238, .9); background: rgba(255, 255, 255, .94); backdrop-filter: blur(14px); }
.header-inner { min-height: 74px; display: flex; align-items: center; gap: 26px; }
.brand { color: var(--ink); text-decoration: none; font-weight: 800; letter-spacing: -.02em; }
.easymp3-brand { display: inline-flex; align-items: center; gap: 11px; margin-right: auto; }
.easymp3-brand img { border-radius: 11px; box-shadow: 0 5px 16px rgba(24, 87, 140, .2); }
.site-header nav, .site-footer nav { display: flex; align-items: center; gap: 22px; }
.site-header nav a, .site-footer nav a, .language-link { color: var(--ink); text-decoration: none; font-weight: 650; }
.site-header nav a:hover, .language-link:hover { color: var(--blue); }
.header-actions { display: flex; align-items: center; gap: 14px; }
.language-link { padding: 7px 12px; border: 1px solid var(--line); border-radius: 999px; font-size: .88rem; }
.menu-button { display: none; border: 1px solid var(--line); border-radius: 10px; padding: 8px 12px; color: var(--ink); background: #fff; font: inherit; }

.hero { overflow: hidden; padding: 84px 0 70px; background: radial-gradient(circle at 80% 18%, rgba(53, 184, 207, .24), transparent 31%), linear-gradient(145deg, #f3f9ff 0%, #fff 54%, #effbfc 100%); }
.hero-inner { display: grid; grid-template-columns: 168px 1fr; align-items: center; gap: 44px; }
.hero img { border-radius: 34px; box-shadow: 0 24px 50px rgba(19, 87, 143, .22); }
.eyebrow, .content-kicker { margin: 0 0 8px; color: var(--blue); font-size: .8rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
h1, h2, h3, h4 { line-height: 1.3; letter-spacing: -.025em; }
.hero h1 { margin: 0; font-size: clamp(2.5rem, 6vw, 4.7rem); }
.lead { max-width: 720px; margin: 17px 0 26px; color: var(--muted); font-size: clamp(1.05rem, 2.4vw, 1.32rem); }
.store-button, .button, .store-link { display: inline-flex; align-items: center; justify-content: center; border: 0; border-radius: 999px; padding: 13px 21px; color: #fff; background: linear-gradient(135deg, var(--blue), var(--blue-dark)); box-shadow: 0 10px 24px rgba(15, 79, 138, .22); text-decoration: none; font-weight: 750; cursor: pointer; }

.quick-links { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: -24px; position: relative; }
.quick-links a { padding: 20px 18px; border: 1px solid var(--line); border-radius: 16px; color: var(--ink); background: #fff; box-shadow: var(--shadow); text-align: center; text-decoration: none; font-weight: 720; }
.quick-links a:hover { border-color: var(--cyan); transform: translateY(-2px); }

.page-head { padding: 62px 0 48px; color: #fff; background: linear-gradient(135deg, var(--blue-dark), var(--blue) 58%, var(--cyan)); }
.page-head h1 { max-width: 850px; margin: 0; font-size: clamp(2rem, 5vw, 3.6rem); }
.page-head p:last-child { max-width: 760px; margin: 16px 0 0; color: rgba(255, 255, 255, .86); }
.page-head .eyebrow { color: #b9f3ff; }
.breadcrumbs { display: flex; gap: 9px; align-items: center; padding-block: 18px; color: var(--muted); font-size: .9rem; }
.breadcrumbs a { color: var(--blue-dark); }

.guide-layout { display: grid; grid-template-columns: minmax(0, 1fr) 278px; align-items: start; gap: 58px; }
.guide-content { min-width: 0; font-size: 1.02rem; }
.guide-content > :first-child { margin-top: 0; }
.guide-content h2 { margin-top: 2.5em; padding-bottom: .35em; border-bottom: 2px solid var(--line); font-size: 1.65rem; }
.guide-content h3 { margin-top: 2.1em; font-size: 1.3rem; }
.guide-content h4 { margin-top: 1.8em; }
.guide-content p, .guide-content li { color: #334357; }
.guide-content a { text-underline-offset: 3px; }
.guide-content img { display: block; width: auto; max-height: 760px; margin: 24px auto; border-radius: 15px; box-shadow: 0 10px 30px rgba(19, 64, 106, .12); }
.guide-content figure { margin: 28px 0; text-align: center; }
.guide-content hr { margin: 42px 0; border: 0; border-top: 1px solid var(--line); }
.guide-content ul, .guide-content ol { padding-left: 1.35em; }
.guide-content li + li { margin-top: .4em; }
.guide-content blockquote { margin: 24px 0; padding: 14px 20px; border-left: 4px solid var(--cyan); background: var(--soft); }
.article-version-note { margin: 0 0 28px; padding: 14px 18px; border: 1px solid #b8d9f0; border-radius: 14px; background: #f1f8fd; font-size: .92rem; }

.page-toc { margin-bottom: 34px; padding: 20px 24px; border: 1px solid var(--line); border-radius: 16px; background: var(--soft); }
.page-toc ol { margin: 10px 0 0; }
.page-toc .toc-level-3 { margin-left: 18px; }
.guide-sidebar { position: sticky; top: 98px; display: flex; flex-direction: column; gap: 10px; padding: 24px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; box-shadow: var(--shadow); }
.guide-sidebar > img { border-radius: 18px; }
.guide-sidebar > strong { font-size: 1.06rem; }
.guide-sidebar > a:not(.store-link) { padding: 8px 0; border-bottom: 1px solid var(--line); color: #334357; text-decoration: none; font-size: .92rem; }
.sidebar-label { margin-top: 12px; color: var(--muted); font-size: .72rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }

.article-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.article-card { min-height: 145px; display: flex; flex-direction: column; padding: 22px; border: 1px solid var(--line); border-radius: 18px; color: var(--ink); background: #fff; text-decoration: none; box-shadow: 0 8px 24px rgba(19, 64, 106, .07); }
.article-card span { color: var(--blue); font-size: .76rem; font-weight: 800; text-transform: uppercase; }
.article-card strong { margin-top: 9px; }
.article-card small { margin-top: auto; align-self: flex-end; font-size: 1.2rem; }

.support-grid { max-width: 820px; }
.contact-notice { margin-bottom: 26px; padding: 18px 20px; border-left: 4px solid var(--cyan); border-radius: 12px; background: var(--soft); }
.contact-notice p { margin-bottom: 0; color: var(--muted); }
.support-form { display: grid; gap: 12px; padding: 30px; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.support-form h2 { margin-top: 0; }
.support-form label { font-weight: 720; }
.support-form input, .support-form select, .support-form textarea { width: 100%; border: 1px solid #b9c8d6; border-radius: 11px; padding: 12px 13px; color: var(--ink); background: #fff; font: inherit; }
.support-form input:focus, .support-form select:focus, .support-form textarea:focus { outline: 3px solid rgba(53, 184, 207, .22); border-color: var(--blue); }
.contact-field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.contact-agreement { display: flex; align-items: flex-start; gap: 10px; font-weight: 500 !important; }
.contact-agreement input { width: auto; margin-top: .45em; }
.contact-honeypot { position: absolute !important; left: -10000px !important; width: 1px !important; height: 1px !important; overflow: hidden !important; }
.cf-turnstile { min-height: 65px; }
.contact-result { min-height: 65vh; display: grid; place-items: center; text-align: center; }
.contact-result-success, .contact-result-error { max-width: 680px; padding: 38px; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.contact-result-success { border-top: 6px solid #2b9b67; }
.contact-result-error { border-top: 6px solid #d55353; }

.embed-page { margin: 0; padding: 18px; background: var(--soft); }
.embed-page article { display: grid; grid-template-columns: 48px 1fr; gap: 14px; align-items: start; max-width: 680px; margin: auto; }
.embed-page img { border-radius: 11px; }
.embed-page p { margin: 4px 0; color: var(--muted); font-size: .9rem; line-height: 1.5; }
.embed-page small { color: var(--muted); }

.status-page { min-height: 62vh; display: grid; place-content: center; justify-items: center; text-align: center; }
.status-code { margin: 0; color: var(--blue); font-size: clamp(5rem, 16vw, 10rem); font-weight: 900; line-height: 1; opacity: .16; }
.status-page h1 { margin-top: -24px; }

.site-footer { padding: 48px 0 22px; color: #d9e8f6; background: #122438; }
.footer-grid { display: flex; justify-content: space-between; gap: 30px; }
.site-footer .brand { color: #fff; font-size: 1.1rem; }
.site-footer nav a { color: #d9e8f6; }
.copyright { margin: 34px 0 0; text-align: center; color: #8fa6bb; font-size: .82rem; }

@media (max-width: 820px) {
  .site-header nav { display: none; position: absolute; top: 74px; left: 20px; right: 20px; flex-direction: column; align-items: stretch; gap: 0; padding: 12px; border: 1px solid var(--line); border-radius: 14px; background: #fff; box-shadow: var(--shadow); }
  .site-header nav[data-open="true"] { display: flex; }
  .site-header nav a { padding: 12px; }
  .menu-button { display: block; }
  .hero-inner { grid-template-columns: 112px 1fr; gap: 26px; }
  .quick-links { grid-template-columns: 1fr 1fr; }
  .guide-layout { grid-template-columns: 1fr; }
  .guide-sidebar { position: static; }
  .article-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 560px) {
  .shell { width: min(100% - 28px, 1120px); }
  .header-inner { min-height: 66px; }
  .easymp3-brand span { font-size: .9rem; }
  .language-link { font-size: .78rem; padding: 6px 9px; }
  .site-header nav { top: 66px; }
  .hero { padding-top: 56px; }
  .hero-inner { grid-template-columns: 1fr; text-align: center; }
  .hero img { width: 112px; margin: auto; }
  .lead { margin-inline: auto; }
  .quick-links, .article-grid, .contact-field-row { grid-template-columns: 1fr; }
  .section { padding-block: 46px; }
  .support-form { padding: 22px 18px; }
  .footer-grid { flex-direction: column; }
  .site-footer nav { align-items: flex-start; flex-direction: column; gap: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}