:root {
    --bg-color: #f7f9fc;
    --card-bg: #ffffff;
    --text-main: #1d1d1f;
    --text-muted: #86868b;
    --primary-color: #007aff;
    --primary-hover: #0062cc;
    --border-color: #e5e5ea;
    --success-bg: #f2fdf4;
    --success-color: #34c759;
}

/* 深色模式适配 */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #000000;
        --card-bg: #1c1c1e;
        --text-main: #f5f5f7;
        --text-muted: #98989d;
        --border-color: #38383a;
        --success-bg: #1e2e22;
    }
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    width: 100%;
    max-width: 800px;
    padding: 20px;
}

.logo-header {
    text-align: center;
    margin-bottom: 40px;
}
.logo-header .logo {
    height: 48px;
    object-fit: contain;
}

.card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    border: 1px solid var(--border-color);
    text-align: center;
}

h2 { font-size: 24px; margin-bottom: 12px; font-weight: 600; }
.subtitle { color: var(--text-muted); margin-bottom: 30px; font-size: 15px; }

/* 选项网格 */
.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    text-align: left;
}

.option-card {
    padding: 24px;
    border: 2px solid var(--border-color);
    border-radius: 16px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.option-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0,122,255,0.1);
}

.option-card h3 { font-size: 18px; margin-bottom: 8px; color: var(--primary-color); }
.option-card p { font-size: 14px; color: var(--text-muted); line-height: 1.5; }

/* 结果页 */
.icon-success {
    font-size: 48px;
    color: var(--success-color);
    margin-bottom: 20px;
}
.reward-box {
    background: var(--success-bg);
    padding: 24px;
    border-radius: 12px;
    margin: 30px 0;
}
.highlight-text {
    font-size: 18px;
    font-weight: 600;
    color: var(--success-color);
    margin-bottom: 20px;
}

.action-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 30px;
}
.action-item {
    padding: 20px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    text-align: left;
}
.action-item h4 { margin-bottom: 10px; }
.action-item p { font-size: 13px; color: var(--text-muted); margin-bottom: 16px; height: 40px; }

/* 按钮 */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    font-size: 15px;
    transition: all 0.2s;
    cursor: pointer;
    border: none;
}
.btn-primary { background: var(--primary-color); color: #fff; width: 100%; max-width: 300px; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-outline { border: 1px solid var(--primary-color); color: var(--primary-color); padding: 8px 16px; font-size: 13px;}
.btn-outline:hover { background: var(--primary-color); color: #fff; }

.support-footer { border-top: 1px solid var(--border-color); padding-top: 20px; color: var(--text-muted); font-size: 12px; }

/* 动画与 Loading */
.hidden { display: none !important; }
.fade-in { animation: fadeIn 0.5s ease forwards; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

#step-loading {
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 300px;
}
.loader {
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 48px;
    height: 48px;
    animation: spin 1s linear infinite;
    margin-bottom: 24px;
}
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }

@media (max-width: 600px) {
    .action-grid { grid-template-columns: 1fr; }
    .action-item p { height: auto; }
}