* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: "PingFang SC", "Microsoft YaHei", sans-serif; background-color: #f5f7fa; color: #333; line-height: 1.6; }
.container { max-width: 1000px; margin: 0 auto; padding: 0 15px; }
.header { background: #fff; height: 64px; box-shadow: 0 2px 8px rgba(0,0,0,0.06); position: sticky; top: 0; z-index: 999; }
.navbar { display: flex; justify-content: space-between; align-items: center; height: 100%; }
.logo { display: flex; align-items: center; font-size: 18px; font-weight: bold; color: #333; }
.logo img { height: 32px; margin-right: 8px; }
.nav a { text-decoration: none; color: #666; margin-left: 20px; font-size: 14px; }
.nav a.active { color: #4facfe; font-weight: bold; }
.card { background: #fff; border-radius: 12px; padding: 25px; margin-top: 20px; box-shadow: 0 4px 12px rgba(0,0,0,0.02); }
.section-title { font-size: 18px; margin-bottom: 20px; border-left: 4px solid #4facfe; padding-left: 12px; }
.input-group { margin-bottom: 25px; }
.input-group label { display: block; margin-bottom: 12px; color: #666; font-size: 14px; }
.input-group input[type="text"] { width: 100%; padding: 12px; border: 1px solid #e1e4e8; border-radius: 8px; outline: none; font-size: 15px; }
.price-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.price-item { position: relative; border: 1px solid #e1e4e8; border-radius: 10px; padding: 15px 10px; text-align: center; cursor: pointer; transition: all 0.2s; background: #fff; }
.price-item.active { border-color: #4facfe; background: rgba(79, 172, 254, 0.05); }
.bonus-tag { position: absolute; top: 6px; right: 6px; padding: 2px 6px; border-radius: 10px; font-size: 11px; line-height: 1.2; color: #fff; background: #ff6b6b; }
.coin-num strong { font-size: 20px; color: #333; }
.coin-num span { font-size: 12px; color: #666; margin-left: 2px; }
.rmb-num { font-size: 13px; color: #999; margin-top: 4px; }
.price-item.active .coin-num strong, .price-item.active .coin-num span { color: #4facfe; }
.pay-methods { display: flex; gap: 14px; }
.pay-methods .pay-item {
    position: relative;
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    flex-wrap: nowrap;
    gap: 10px;
    white-space: nowrap;
    margin-bottom: 0;
    cursor: pointer;
    padding: 14px 16px;
    border: 1px solid #e8ebf0;
    border-radius: 12px;
    background: #fff;
    transition: all 0.2s ease;
}
.pay-methods .pay-item:hover {
    border-color: #bcdcff;
    transform: translateY(-1px);
}
.pay-methods .pay-item.active {
    border-color: #4facfe;
    background: linear-gradient(135deg, rgba(79, 172, 254, 0.12), rgba(79, 172, 254, 0.04));
    box-shadow: 0 8px 20px rgba(79, 172, 254, 0.18);
}
.pay-methods .pay-item img { height: 24px; }
.pay-methods .pay-item img { width: 24px; flex: 0 0 24px; object-fit: contain; display: block; }
.pay-methods .pay-item span { display: inline-flex; align-items: center; line-height: 24px; white-space: nowrap; color: #48505e; font-weight: 500; }
.pay-methods .pay-item.active span { color: #2b7fd6; }
.pay-methods .pay-item input {
    position: absolute;
    width: 1px;
    height: 1px;
    opacity: 0;
    pointer-events: none;
}
.submit-btn { width: 100%; padding: 16px; background: #4facfe; color: #fff; border: none; border-radius: 30px; font-size: 16px; font-weight: bold; cursor: pointer; margin-top: 10px; transition: opacity 0.3s; }
.submit-btn:hover { opacity: 0.9; }
.download-grid { display: flex; justify-content: space-around; padding: 20px 0; }
.dl-item { position: relative; text-align: center; }
.dl-btn { height: 45px; cursor: pointer; transition: transform 0.2s; }
.dl-btn:hover { transform: translateY(-3px); }
.qr-pop { 
    position: absolute; bottom: 55px; left: 50%; transform: translateX(-50%);
    background: #fff; padding: 10px; border-radius: 8px; box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    display: none; width: 140px; z-index: 10;
}
.qr-pop img { width: 120px; height: 120px; }
.qr-pop p { font-size: 12px; color: #666; margin-top: 5px; }

.dl-item:hover .qr-pop { display: block; }
.faq-section {
    background: linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
}
.faq-intro {
    margin: -6px 0 16px;
    font-size: 13px;
    color: #7a8699;
}
.faq-list {
    display: grid;
    gap: 12px;
}
.faq-item {
    border: 1px solid #e7edf5;
    border-radius: 14px;
    background: #fff;
    box-shadow: 0 8px 20px rgba(60, 96, 160, 0.06);
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
    overflow: hidden;
}
.faq-item:hover {
    border-color: #c6ddff;
    box-shadow: 0 12px 26px rgba(63, 120, 218, 0.14);
    transform: translateY(-2px);
}
.faq-item summary {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 16px;
    cursor: pointer;
    font-size: 15px;
    font-weight: 600;
    color: #253043;
}
.faq-item summary::-webkit-details-marker {
    display: none;
}
.faq-item summary::after {
    content: "+";
    margin-left: auto;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f1f7ff;
    color: #4facfe;
    font-size: 18px;
    font-weight: 500;
    transition: transform 0.2s ease, background-color 0.2s ease, color 0.2s ease;
}
.faq-item[open] summary::after {
    content: "-";
    transform: rotate(180deg);
    background: #4facfe;
    color: #fff;
}
.faq-tag {
    min-width: 34px;
    padding: 4px 8px;
    border-radius: 999px;
    font-size: 12px;
    font-weight: 700;
    text-align: center;
    color: #2b7fd6;
    background: rgba(79, 172, 254, 0.14);
}
.faq-question {
    flex: 1;
}
.faq-item p {
    padding: 0 16px 16px 16px;
    font-size: 14px;
    color: #576275;
    line-height: 1.75;
}
.faq-answer-tag {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    margin-right: 8px;
    font-size: 12px;
    font-weight: 700;
    color: #fff;
    background: linear-gradient(135deg, #42d392, #1ea66f);
    vertical-align: top;
}
.footer { background: #1a1a1a; color: #666; padding: 40px 0; text-align: center; font-size: 12px; margin-top: 40px; }
.footer-links { margin-bottom: 15px; }
.footer-links a { color: #888; text-decoration: none; margin: 0 8px; }
@media (max-width: 768px) {
    .header { height: 56px; }
    .navbar { justify-content: flex-start; }
    .nav { display: none; }
    .logo { font-size: 16px; }
    .logo img { height: 28px; }
    .price-grid { grid-template-columns: repeat(2, 1fr); }
    .download-grid { flex-direction: column; align-items: center; gap: 20px; }
    .qr-pop { position: static; transform: none; display: block; margin-top: 10px; box-shadow: none; width: 120px; }
    .pay-methods { flex-direction: column; gap: 10px; }
    .faq-item summary { padding: 13px 12px; gap: 8px; font-size: 14px; }
    .faq-tag { min-width: 30px; padding: 3px 7px; font-size: 11px; }
    .faq-item p { padding: 0 12px 13px; font-size: 13px; }
}