/* === 强制锁定：IELTS Pro 配色 (修复排版版) === */
:root {
    --bg-body: #F4F7FE !important;
    --bg-sidebar: #FFFFFF !important;
    --bg-card: #FFFFFF !important;
    
    /* 修复点1：加深文字颜色，确保看得清 */
    --text-primary: #2B3674 !important;   /* 深蓝黑标题 */
    --text-secondary: #707EAE !important; /* 加深的灰蓝，不再隐形 */
    --text-white: #FFFFFF !important;
    
    --accent-color: #4318FF !important;
    --shadow-card: 0px 18px 40px rgba(112, 144, 176, 0.12) !important;
    --font-stack: "DM Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; outline: none; }

body {
    font-family: var(--font-stack);
    background-color: var(--bg-body) !important;
    color: var(--text-primary) !important;
    height: 100vh;
    overflow: hidden;
    display: flex;
}

/* --- 左侧边栏 (精细化排版) --- */
.sidebar {
    width: 260px; /* 稍微调窄一点，更精致 */
    background-color: var(--bg-sidebar) !important;
    display: flex;
    flex-direction: column;
    padding: 30px 0;
    flex-shrink: 0;
    box-shadow: 10px 0 30px rgba(0,0,0,0.02); 
}

.logo-area { padding: 0 32px 30px 32px; }
.logo-link svg { fill: var(--text-primary) !important; height: 32px; }

.nav-tree { padding: 0 20px; list-style: none; overflow-y: auto; }
.nav-item { margin-bottom: 4px; } /* 减小间距 */

/* 菜单项 */
.nav-link {
    display: flex; align-items: center;
    color: var(--text-secondary) !important; /* 现在是深灰色了 */
    padding: 10px 16px; /* 减小内边距，不像按钮 */
    border-radius: 10px;
    font-size: 14px;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.2s ease;
}

.nav-link:hover {
    color: var(--accent-color) !important;
    background-color: rgba(67, 24, 255, 0.05);
}

/* 选中状态 */
.nav-link.active {
    background-color: var(--accent-color) !important;
    color: var(--text-white) !important;
    font-weight: 600;
    box-shadow: 0 5px 15px rgba(67, 24, 255, 0.3);
}
.icon-folder { margin-right: 10px; font-size: 16px; opacity: 0.8; }
.nav-link.active .icon-folder { opacity: 1; color: #fff; }

/* --- 右侧内容区 --- */
.main-content {
    flex-grow: 1; display: flex; flex-direction: column;
    background-color: var(--bg-body) !important;
}

/* 顶部栏：参考图的关键，左边标题，右边按钮 */
header {
    height: 90px; 
    display: flex; 
    align-items: center; 
    justify-content: space-between;
    padding: 0 40px;
    background: transparent;
}

/* 顶部大标题 */
.page-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}

/* 按钮：复刻右上角蓝色按钮 */
.action-btn {
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 10px 24px;
    border-radius: 30px;
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(67, 24, 255, 0.2);
    display: inline-flex; align-items: center; gap: 6px;
}
.action-btn:hover { transform: translateY(-2px); }

.workspace {
    padding: 0 40px 40px 40px;
    overflow-y: auto;
    height: calc(100vh - 90px);
}

/* --- 白色大卡片 --- */
.card-container {
    background-color: var(--bg-card) !important;
    border-radius: 24px;
    padding: 40px;
    box-shadow: var(--shadow-card);
    min-height: 80%;
}

/* 标签池 */
.vocab-pool {
    display: flex; flex-wrap: wrap; gap: 14px;
    padding: 30px;
    border-radius: 20px;
    background-color: #FAFCFE; 
    border: 1px dashed #E0E5F2; 
    margin-top: 20px;
}

.vocab-tag {
    background-color: #FFFFFF !important;
    color: var(--text-primary) !important;
    border: none;
    padding: 10px 20px;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 3px 6px rgba(112, 144, 176, 0.08);
}
.vocab-tag:hover {
    transform: translateY(-2px);
    color: var(--accent-color) !important;
}

/* Modal */
.modal-overlay { background: rgba(43, 54, 116, 0.2) !important; backdrop-filter: blur(4px); display:none; justify-content:center; align-items:center; position:fixed; top:0; left:0; width:100%; height:100%; z-index:999;}
.modal-overlay.active { display: flex; }
.modal-card { background: #fff !important; width: 500px; border-radius: 24px; padding: 40px; box-shadow: 0 20px 60px rgba(0,0,0,0.1); position: relative; }
.close-modal { position: absolute; top: 20px; right: 20px; border:none; background:none; font-size:24px; cursor:pointer; color: #ccc;}