:root {
    color-scheme: light;
    font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    --brand: #2b90d9;
    --accent: #f7b733;
    --bg-light: #f7f9fc;
    --text-dark: #1f2d3d;
}

body {
    margin: 0;
    background: white;
    color: var(--text-dark);
}

.hero {
    background: linear-gradient(135deg, rgba(43,144,217,0.9), rgba(247,183,51,0.9)), url('../images/placeholder-hero.jpg') center/cover;
    color: #fff;
    padding: 5rem 1.5rem;
    text-align: center;
}

.hero .container { max-width: 960px; margin: 0 auto; }
.hero h1 { font-size: 2.75rem; margin-bottom: 0.5rem; }
.hero p { font-size: 1.2rem; margin-bottom: 1.5rem; }
.cta {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: var(--accent);
    color: #1f2d3d;
    border-radius: 999px;
    text-decoration: none;
    font-weight: bold;
    transition: transform 0.2s ease;
}
.cta:hover { transform: translateY(-2px); }

main { padding: 3rem 1.5rem 4rem; background: var(--bg-light); }
section { max-width: 1100px; margin: 0 auto 3rem; background: #fff; border-radius: 12px; padding: 2rem; box-shadow: 0 8px 24px rgba(15,35,95,0.06); }
section h2 { margin-top: 0; }

.two-column { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 2rem; align-items: center; }
.two-column img { width: 100%; border-radius: 8px; background: #d9e5f6; aspect-ratio: 16/10; object-fit: cover; }

.one-column { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 2rem; align-items: center; }
.one-column img { width: 100%; border-radius: 8px; background: #d9e5f6; aspect-ratio: 16/5; object-fit: cover; }
.one-column figure figcaption{ margin-top: 0.75rem; font-size: 0.9rem; color: #000000; }

figure { margin: 0; }
figcaption { margin-top: 0.75rem; font-size: 0.9rem; color: #5b6c7d; }

.steps-grid { display: grid; gap: 1.5rem; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.steps-grid article { background: #fdfdfd; border: 1px solid #e4e9f0; border-radius: 10px; padding: 1.5rem; display: flex; flex-direction: column; }
.steps-grid article img { width: 100%; border-radius: 8px; background: #d9e5f6; aspect-ratio: 16/10; object-fit: cover; margin-bottom: 1rem; }
.steps-grid h3 { margin-top: 0; color: var(--brand); }

.guide ol { padding-left: 1.2rem; }
.guide li { margin-bottom: 0.8rem; }

summary { cursor: pointer; font-weight: 600; color: var(--brand); }
details[open] summary { color: #123a58; }

footer { background: #15202b; color: #f2f5f7; padding: 2rem 1.5rem; position: relative; }
footer .container { max-width: 960px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 1rem; }
#back-to-top { background: var(--accent); border: none; padding: 0.6rem 1rem; border-radius: 999px; font-weight: 600; cursor: pointer; }
#back-to-top.hidden { display: none; }

@media (max-width: 640px) {
    .hero h1 { font-size: 2rem; }
    section { padding: 1.5rem; }
}