:root {
    --bg-color: #ffffff;
    --text-color: #222222;
    --card-bg: #f8f9fa;
    --border-color: #dddddd;
    --accent-color: #2563eb;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --card-bg: #1e1e1e;
    --border-color: #333333;
    --accent-color: #3b82f6;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: system-ui, -apple-system, sans-serif;
    margin: 0;
    line-height: 1.6;
}

.container { max-width: 900px; margin: 0 auto; padding: 15px; }
header { border-bottom: 1px solid var(--border-color); }
.header-content { display: flex; justify-content: space-between; align-items: center; }

button {
    background: var(--accent-color);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 4px;
    cursor: pointer;
}
.btn-danger { background: #dc2626; }

.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 20px;
    margin-bottom: 20px;
    border-radius: 6px;
}

.hidden { display: none !important; }

.categories { display: flex; gap: 10px; margin-bottom: 20px; }
.categories button { background: var(--card-bg); color: var(--text-color); border: 1px solid var(--border-color); }
.categories button.active { background: var(--accent-color); color: white; }

.articles-grid { display: flex; flex-direction: column; gap: 10px; }
.article-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 15px;
    border-radius: 6px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.article-body img { max-width: 100%; height: auto; }
.article-body table { width: 100%; border-collapse: collapse; margin: 15px 0; }
.article-body th, .article-body td { border: 1px solid var(--border-color); padding: 8px; }
.meta { color: #888; font-size: 0.9em; margin-bottom: 15px; }

.header-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    height: 38px;
    padding: 0 16px;
    box-sizing: border-box;
    font-size: 14px;
    font-weight: 500;
    line-height: 1;
    border-radius: 6px;
    border: 1px solid transparent;
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s;
}

.theme-toggle-btn,
.login-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    height: 38px;
    padding: 0 16px;
    box-sizing: border-box;
    font-size: 14px;
    line-height: 1;
}