:root {
    --color-primary: #007aff;
    --color-danger: #ff3b30;
    --color-success: #34c759;
    --color-gray: #8e8e93;
    --color-bg: #f2f2f7;
    --color-card: #ffffff;
    --radius: 12px;
    --space: 16px;
    --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    --font-size: 1rem;
    --font-small: 0.85rem;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", Helvetica, Arial, sans-serif;
    background: var(--color-bg);
    color: #000;
    line-height: 1.5;
    padding: var(--space);
    padding-bottom: 80px;
}

/* 卡片 */
.card {
    background: var(--color-card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: var(--space);
    margin-bottom: 20px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

/* 登录卡片 */
.login-card h1 {
    font-size: 1.5rem;
    margin-bottom: 12px;
    text-align: center;
}

/* 提示 */
.alert {
    padding: 10px;
    border-radius: 8px;
    font-size: var(--font-small);
    margin-bottom: var(--space);
}

.alert.error {
    background: rgba(255, 59, 48, 0.1);
    color: var(--color-danger);
}

.alert.success {
    background: rgba(52, 199, 89, 0.1);
    color: var(--color-success);
}

/* 表单 */
input[type="text"],
input[type="password"],
textarea,
input[type="file"] {
    width: 100%;
    padding: 12px;
    border: 0.5px solid rgba(60, 60, 67, 0.18);
    border-radius: 8px;
    margin-top: 6px;
    background: #f9f9fb;
    font-size: var(--font-size);
    transition: border-color 0.2s;
}

input:focus,
textarea:focus {
    border-color: var(--color-primary);
    outline: none;
}

textarea {
    resize: vertical;
    min-height: 120px;
}

.btn {
    display: block;
    width: 100%;
    text-align: center;
    padding: 12px;
    font-size: var(--font-size);
    font-weight: 500;
    border: none;
    border-radius: 8px;
    margin-top: 12px;
    cursor: pointer;
    transition: opacity 0.2s;
}

.btn:hover {
    opacity: 0.9;
}

.btn-primary {
    background: var(--color-primary);
    color: white;
}

.btn-danger {
    background: var(--color-danger);
    color: white;
}

.form-tip {
    font-size: var(--font-small);
    color: var(--color-gray);
    text-align: center;
    margin-top: 8px;
}

.empty-text {
    text-align: center;
    color: var(--color-gray);
    padding: 20px 0;
}

/* 顶部导航 */
.top-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.top-nav .btn-logout {
    color: var(--color-danger);
    text-decoration: none;
    font-size: var(--font-small);
}

/* 规则卡片 */
.rule-card {
    background: #f9f9fb;
    border-radius: 10px;
    padding: 12px 16px;
    margin-bottom: 12px;
}

.rule-content {
    font-size: var(--font-size);
    white-space: pre-wrap;
    word-break: break-all;
}

.rule-meta {
    font-size: var(--font-small);
    color: var(--color-gray);
    margin-top: 6px;
}

.screenshot-preview,
.screenshot-thumb {
    max-width: 150px;
    margin-top: 8px;
    border-radius: 8px;
}

/* 底部导航 */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: #f9f9fb;
    border-top: 0.5px solid rgba(60, 60, 67, 0.18);
    display: flex;
    z-index: 999;
}

.bottom-nav .nav-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    color: var(--color-gray);
    text-decoration: none;
}

.bottom-nav .nav-item.active {
    color: var(--color-primary);
}

.nav-icon {
    font-size: 1.2rem;
    margin-bottom: 4px;
}

/* 响应式 */
@media (min-width: 768px) {
    body {
        padding: 24px;
        padding-bottom: 90px;
    }
    .card {
        padding: 20px;
    }
}