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

body {
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 48px 24px;
    background: #f5f5f7;
    color: #1d1d1f;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}

.card {
    width: 100%;
    max-width: 480px;
    background: #ffffff;
    border-radius: 28px;
    padding: 48px 40px 36px;
    text-align: center;
    box-shadow:
        0 1px 3px rgba(0, 0, 0, 0.04),
        0 12px 40px rgba(0, 0, 0, 0.08);
    animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
}

.header {
    margin-bottom: 28px;
}

.logo {
    width: 72px;
    height: 72px;
    margin: 0 auto 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 34px;
    background: #1d1d1f;
    border-radius: 20px;
}

h1 {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.015em;
    color: #1d1d1f;
    margin-bottom: 6px;
    text-wrap: balance;
}

.subtitle {
    font-size: 14px;
    color: #6e6e73;
    letter-spacing: 0.5px;
}

.desc {
    font-size: 16px;
    line-height: 1.7;
    color: #424245;
    margin-bottom: 22px;
    text-wrap: pretty;
}

.features {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 32px;
}

.features span {
    font-size: 13px;
    color: #1d1d1f;
    background: #f5f5f7;
    padding: 8px 14px;
    border-radius: 999px;
    font-weight: 500;
}

.qr-wrap {
    display: inline-block;
    cursor: zoom-in;
    margin-bottom: 30px;
}

.qr-frame {
    background: #ffffff;
    padding: 14px;
    border-radius: 22px;
    box-shadow:
        0 0 0 1px rgba(0, 0, 0, 0.06),
        0 14px 36px rgba(0, 0, 0, 0.08);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.qr-wrap:hover .qr-frame {
    transform: translateY(-3px);
    box-shadow:
        0 0 0 1px rgba(0, 0, 0, 0.08),
        0 20px 48px rgba(0, 0, 0, 0.1);
}

.qr-frame img {
    display: block;
    max-width: 240px;
    width: 100%;
    height: auto;
    border-radius: 14px;
}

.qr-caption {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-top: 18px;
    padding: 11px 24px;
    background: #1d1d1f;
    color: #ffffff;
    font-size: 15px;
    font-weight: 600;
    border-radius: 999px;
}

.feedback {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    text-align: left;
    background: #f5f5f7;
    border-radius: 18px;
    padding: 18px 20px;
    margin-bottom: 28px;
}

.feedback-icon {
    font-size: 22px;
    flex-shrink: 0;
    margin-top: 2px;
}

.feedback-title {
    font-size: 15px;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 2px;
}

.feedback-body p:last-child {
    font-size: 14px;
    line-height: 1.6;
    color: #6e6e73;
}

.feedback a {
    color: #0071e3;
    font-weight: 600;
    text-decoration: none;
}

.feedback a:hover {
    text-decoration: underline;
}

.sponsors {
    border-top: 1px solid #e8e8ed;
    padding-top: 28px;
    margin-bottom: 28px;
}

.sponsors h2 {
    font-size: 18px;
    font-weight: 700;
    color: #1d1d1f;
    margin-bottom: 8px;
}

.sponsors-note {
    font-size: 13px;
    color: #86868b;
    margin-bottom: 16px;
    line-height: 1.5;
}

.sponsors-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.sponsors-list li {
    font-size: 14px;
    font-weight: 500;
    color: #1d1d1f;
    background: #f5f5f7;
    padding: 8px 12px;
    border-radius: 999px;
    text-align: center;
    line-height: 1.4;
    word-break: break-all;
    overflow-wrap: anywhere;
    min-height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sponsors-empty {
    font-size: 14px;
    color: #86868b;
}

footer {
    font-size: 14px;
    color: #86868b;
}

.heart {
    display: inline-block;
    animation: heartbeat 1.5s ease-in-out infinite;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    15% { transform: scale(1.2); }
    30% { transform: scale(1); }
    45% { transform: scale(1.15); }
}

/* 灯箱 */
.lightbox {
    position: fixed;
    inset: 0;
    z-index: 100;
    display: none;
    justify-content: center;
    align-items: center;
    padding: 24px;
    opacity: 0;
    transition: opacity 0.25s ease;
}

.lightbox.active {
    display: flex;
    opacity: 1;
}

.lightbox-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.72);
    backdrop-filter: blur(6px);
    cursor: pointer;
}

.lightbox-content {
    position: relative;
    z-index: 101;
    background: #ffffff;
    border-radius: 24px;
    padding: 28px;
    max-width: 420px;
    width: 100%;
    text-align: center;
    box-shadow: 0 30px 80px rgba(0, 0, 0, 0.35);
    transform: scale(0.95);
    transition: transform 0.25s ease;
}

.lightbox.active .lightbox-content {
    transform: scale(1);
}

.lightbox-content img {
    max-width: 100%;
    border-radius: 16px;
}

.lightbox-content p {
    margin-top: 16px;
    font-size: 17px;
    font-weight: 600;
    color: #1d1d1f;
}

.lightbox-close {
    position: absolute;
    top: -14px;
    right: -14px;
    width: 40px;
    height: 40px;
    border: none;
    border-radius: 50%;
    background: #ffffff;
    color: #6e6e73;
    font-size: 28px;
    line-height: 1;
    cursor: pointer;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.18);
    transition: transform 0.2s ease, color 0.2s ease;
}

.lightbox-close:hover {
    color: #1d1d1f;
    transform: rotate(90deg);
}

@media (max-width: 520px) {
    body {
        padding: 24px 16px;
        background: #ffffff;
    }

    .card {
        padding: 32px 20px 28px;
        box-shadow: none;
        border-radius: 0;
    }

    h1 {
        font-size: 26px;
    }

    .desc {
        font-size: 15px;
    }

    .qr-frame img {
        max-width: 210px;
    }

    .feedback {
        padding: 16px;
    }

    .sponsors-list {
        grid-template-columns: repeat(2, 1fr);
    }
}