:root {
      --bg-page: #f9fafb;
      --bg-header: #ffffff;
      --bg-hero: #eef2ff;
      --bg-article: #ffffff;
      --bg-section-alt: #f3f4ff;
      --text-main: #111827;
      --text-soft: #6b7280;
      --accent: #0f766e;
      --accent-soft: #df0c0c;
      --border-soft: #e5e7eb;
      --radius-md: 12px;
      --radius-lg: 20px;
      --shadow-soft: 0 14px 35px rgba(15, 23, 42, 0.12);
      --max-width: 960px;
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
      background-color: var(--bg-page);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    a {
      color: var(--accent);
      text-decoration: none;
    }

    a:hover {
      text-decoration: underline;
    }

    .page {
      min-height: 100vh;
      display: flex;
      flex-direction: column;
    }

    /* HEADER */

    header {
      background-color: var(--bg-header);
      border-bottom: 1px solid rgba(209, 213, 219, 0.8);
    }

    .header-inner {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0.8rem 1.2rem;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 1rem;
    }

    .brand {
      display: flex;
      align-items: center;
      gap: 0.65rem;
    }

    .brand-mark {
      width: 36px;
      height: 36px;
      border-radius: 999px;
      border: 2px solid #22c55e;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 0.8rem;
      font-weight: 800;
      letter-spacing: 0.08em;
      color: #16a34a;
    }

    .brand-text-main {
      font-weight: 700;
      font-size: 1rem;
    }

    .brand-text-sub {
      font-size: 0.78rem;
      color: var(--text-soft);
    }

    .nav-main {
      display: flex;
      align-items: center;
      gap: 0.75rem;
      font-size: 0.86rem;
    }

    .nav-pill {
      padding: 0.2rem 0.6rem;
      border-radius: 999px;
      background-color: #ecfeff;
      color: #0f766e;
      font-size: 0.76rem;
    }

    .nav-link {
      color: var(--text-soft);
    }

    main {
      flex: 1;
    }

    /* LAYOUT */

    .container {
      max-width: var(--max-width);
      margin: 1.4rem auto 2.4rem;
      padding: 0 1.2rem;
    }

    .hero {
      background: radial-gradient(circle at top left, #e0f2fe 0, var(--bg-hero) 55%, #e5e7eb 100%);
      border-radius: var(--radius-lg);
      padding: 1.4rem 1.5rem 1.1rem;
      box-shadow: var(--shadow-soft);
      margin-bottom: 1.4rem;
    }

    .hero-kicker {
      font-size: 0.75rem;
      text-transform: uppercase;
      letter-spacing: 0.16em;
      color: #4b5563;
      margin-bottom: 0.4rem;
    }

    .hero-title {
      font-size: clamp(1.6rem, 1.4rem + 1vw, 2.1rem);
      line-height: 1.25;
      margin-bottom: 0.45rem;
    }

    .hero-sub {
      font-size: 0.95rem;
      color: var(--text-soft);
      max-width: 38rem;
      margin-bottom: 0.7rem;
    }

    .hero-meta {
      display: flex;
      flex-wrap: wrap;
      gap: 0.4rem;
      font-size: 0.78rem;
      color: var(--text-soft);
    }

    .badge {
      border-radius: 999px;
      padding: 0.2rem 0.6rem;
      background-color: rgba(15, 118, 110, 0.06);
      border: 1px solid rgba(45, 212, 191, 0.8);
      color: #0f766e;
    }

    .hero-toc {
      margin-top: 0.7rem;
      padding-top: 0.6rem;
      border-top: 1px dashed rgba(148, 163, 184, 0.7);
      font-size: 0.86rem;
    }

    .hero-toc-title {
      font-weight: 600;
      margin-bottom: 0.25rem;
    }

    .hero-toc ul {
      list-style: none;
      display: flex;
      flex-wrap: wrap;
      gap: 0.6rem;
    }

    .hero-toc a {
      font-size: 0.82rem;
      color: #4b5563;
    }

    .hero-toc a::before {
      content: "• ";
      color: var(--accent);
    }

    /* ARTICLE + SIDEPANEL */

    .layout-main {
      display: grid;
      grid-template-columns: minmax(0, 2.1fr) minmax(0, 1.1fr);
      gap: 1.5rem;
      margin-top: 0.8rem;
    }

    article {
      background-color: var(--bg-article);
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-soft);
      box-shadow: var(--shadow-soft);
      padding: 1.3rem 1.4rem 1.5rem;
      font-size: 0.95rem;
    }

    article section + section {
      margin-top: 1rem;
      padding-top: 0.7rem;
      border-top: 1px solid rgba(229, 231, 235, 0.9);
    }

    article h2 {
      font-size: 1.1rem;
      margin-bottom: 0.3rem;
    }

    article h3 {
      font-size: 0.98rem;
      margin: 0.55rem 0 0.3rem;
    }

    article p {
      margin-bottom: 0.5rem;
      color: var(--text-soft);
    }

    article strong {
      color: var(--text-main);
    }

    article ul {
      margin: 0.3rem 0 0.7rem;
      padding-left: 1.1rem;
      color: var(--text-soft);
    }

    article li {
      margin-bottom: 0.3rem;
    }

    .tips-box {
      margin: 0.6rem 0;
      padding: 0.7rem 0.8rem;
      border-radius: var(--radius-md);
      background-color: var(--accent-soft);
      border: 1px solid rgba(34, 197, 174, 0.7);
      font-size: 0.88rem;
      color: #ffffff;
    }

    .warning-box {
      margin: 0.7rem 0 0.2rem;
      padding: 0.7rem 0.8rem;
      border-radius: var(--radius-md);
      background-color: #fef2f2;
      border: 1px solid #fecaca;
      font-size: 0.86rem;
      color: #981b1b;
    }

    .side-panel {
      display: flex;
      flex-direction: column;
      gap: 1rem;
    }

    .side-card {
      background-color: #ffffff;
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-soft);
      box-shadow: var(--shadow-soft);
      padding: 0.9rem 1rem 1rem;
      font-size: 0.88rem;
      color: var(--text-soft);
    }

    .side-card h3 {
      font-size: 0.96rem;
      margin-bottom: 0.3rem;
      color: var(--text-main);
    }

    .side-label {
      font-size: 0.75rem;
      text-transform: uppercase;
      letter-spacing: 0.14em;
      color: #9ca3af;
      margin-bottom: 0.25rem;
    }

    .tag-row {
      display: flex;
      flex-wrap: wrap;
      gap: 0.3rem;
      margin-top: 0.4rem;
    }

    .tag {
      padding: 0.16rem 0.5rem;
      border-radius: 999px;
      background-color: #f3f4f6;
      font-size: 0.74rem;
      color: #6b7280;
    }

    footer {
      border-top: 1px solid var(--border-soft);
      background-color: #f3f4f6;
      padding: 0.9rem 1.2rem 1.2rem;
      font-size: 0.8rem;
      color: var(--text-soft);
    }

    .footer-inner {
      max-width: var(--max-width);
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 0.4rem;
    }

    .footer-top {
      display: flex;
      flex-wrap: wrap;
      justify-content: space-between;
      gap: 0.5rem;
    }

    .footer-links {
      display: flex;
      flex-wrap: wrap;
      gap: 0.6rem;
    }

    .footer-links a {
      color: var(--text-soft);
    }

    @media (max-width: 880px) {
      .layout-main {
        grid-template-columns: minmax(0, 1fr);
      }
    }

    @media (max-width: 640px) {
      .nav-main {
        display: none;
      }
      .container {
        margin-top: 1rem;
      }
      .hero {
        padding: 1.1rem 1rem 1rem;
      }
      article {
        padding: 1.1rem 1rem 1.2rem;
      }
    }