/* ── numbfish-edu-agent 前端样式 v2 ── */

:root {
    --primary: #4A90D9;
    --primary-dark: #357ABD;
    --success: #52C41A;
    --warning: #FAAD14;
    --danger: #FF4D4F;
    --bg: #F5F7FA;
    --card-bg: #FFFFFF;
    --text: #2C3E50;
    --text-secondary: #7F8C8D;
    --border: #E8ECF1;
    --shadow: 0 2px 8px rgba(0,0,0,0.08);
    --radius: 12px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    height: 100vh;
    overflow: hidden;
}

/* ── 布局 ── */
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    max-width: 1200px;
    margin: 0 auto;
}

.app-header {
    background: linear-gradient(135deg, #4A90D9, #357ABD);
    color: white;
    padding: 10px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 2px 12px rgba(74,144,217,0.3);
    z-index: 100;
}

.app-header h1 {
    font-size: 20px;
    font-weight: 600;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

.subject-select {
    padding: 6px 12px;
    border: 1px solid rgba(255,255,255,0.3);
    border-radius: 8px;
    background: rgba(255,255,255,0.15);
    color: white;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    outline: none;
    min-width: 120px;
}

.subject-select option {
    background: white;
    color: var(--text);
}

.subject-select:focus {
    border-color: rgba(255,255,255,0.6);
    background: rgba(255,255,255,0.25);
}

.subtitle {
    font-size: 12px;
    opacity: 0.85;
    min-width: 80px;
    text-align: right;
}

/* ── 标签导航 ── */
.tab-nav {
    display: flex;
    gap: 0;
    background: var(--card-bg);
    border-bottom: 2px solid var(--border);
    padding: 0 24px;
}

.tab-btn {
    padding: 14px 28px;
    border: none;
    background: none;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    border-bottom: 3px solid transparent;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 6px;
}

.tab-btn:hover { color: var(--primary); }
.tab-btn.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
    font-weight: 600;
}

/* ── 内容区 ── */
.tab-content { flex: 1; overflow: hidden; display: none; }
.tab-content.active { display: flex; }

/* ── 聊天Tab ── */
.chat-layout { display: flex; flex: 1; overflow: hidden; }

.chat-sidebar {
    width: 240px;
    background: var(--card-bg);
    border-right: 1px solid var(--border);
    padding: 16px;
    overflow-y: auto;
}

.chat-sidebar h3 {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.concept-list { list-style: none; }

.concept-item {
    padding: 10px 12px;
    border-radius: 8px;
    cursor: pointer;
    margin-bottom: 4px;
    font-size: 13px;
    transition: background 0.15s;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.concept-item:hover { background: #F0F5FF; }
.concept-item.active { background: #E6F0FF; color: var(--primary); font-weight: 500; }

.mastery-bar {
    width: 36px; height: 5px;
    background: #E8ECF1;
    border-radius: 3px;
    overflow: hidden;
}

.mastery-bar-fill {
    height: 100%;
    border-radius: 3px;
    transition: width 0.3s;
}

.mastery-low { background: var(--danger); }
.mastery-mid { background: var(--warning); }
.mastery-high { background: var(--success); }

.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--card-bg);
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.chat-message {
    display: flex;
    gap: 10px;
    max-width: 80%;
    animation: fadeIn 0.3s;
}

@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

.chat-message.user { align-self: flex-end; flex-direction: row-reverse; }
.chat-message.assistant { align-self: flex-start; }

.chat-avatar {
    width: 36px; height: 36px;
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-size: 18px; flex-shrink: 0;
}

.chat-message.user .chat-avatar { background: #E6F0FF; }
.chat-message.assistant .chat-avatar { background: #F0F5FF; }

.chat-bubble {
    padding: 12px 16px;
    border-radius: 12px;
    font-size: 14px; line-height: 1.6;
    white-space: pre-wrap; word-break: break-word;
}

.chat-message.user .chat-bubble {
    background: var(--primary); color: white;
    border-bottom-right-radius: 4px;
}

.chat-message.assistant .chat-bubble {
    background: #F0F5FF;
    border-bottom-left-radius: 4px;
}

.chat-bubble img {
    max-width: 100%; border-radius: 8px; margin-top: 8px;
}

.chat-input-area {
    padding: 16px 20px;
    border-top: 1px solid var(--border);
    display: flex; gap: 10px;
}

.chat-input-area textarea {
    flex: 1;
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 10px 14px;
    font-size: 14px; resize: none; height: 50px;
    font-family: inherit; outline: none;
    transition: border-color 0.2s;
}

.chat-input-area textarea:focus { border-color: var(--primary); }

.btn {
    padding: 10px 20px; border: none; border-radius: 10px;
    font-size: 14px; font-weight: 500; cursor: pointer;
    transition: all 0.2s;
}

.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-success { background: var(--success); color: white; }
.btn-outline {
    background: white; border: 1px solid var(--border); color: var(--text);
}
.btn-outline:hover { border-color: var(--primary); }

/* ── 测评Tab ── */
.quiz-layout {
    flex: 1; overflow-y: auto; padding: 24px;
    display: flex; flex-direction: column; gap: 20px;
}

.quiz-controls {
    display: flex; gap: 12px; align-items: center; flex-wrap: wrap;
}

.quiz-controls select, .quiz-controls input {
    padding: 8px 12px; border: 1px solid var(--border);
    border-radius: 8px; font-size: 14px;
}

.question-card {
    background: var(--card-bg); border-radius: var(--radius);
    padding: 20px; box-shadow: var(--shadow);
}

.question-card .q-header {
    display: flex; justify-content: space-between;
    margin-bottom: 12px; font-size: 13px; color: var(--text-secondary);
}

.question-card .q-content {
    font-size: 15px; line-height: 1.8; margin-bottom: 16px;
}

.options-list {
    display: flex; flex-direction: column; gap: 8px;
}

.option-item {
    padding: 12px 16px; border: 1px solid var(--border);
    border-radius: 8px; cursor: pointer; transition: all 0.15s; font-size: 14px;
}

.option-item:hover { border-color: var(--primary); background: #F0F5FF; }
.option-item.selected { border-color: var(--primary); background: #E6F0FF; font-weight: 500; }
.option-item.correct { border-color: var(--success); background: #F6FFED; }
.option-item.wrong { border-color: var(--danger); background: #FFF2F0; }

.quiz-result { text-align: center; padding: 40px; }
.quiz-score { font-size: 48px; font-weight: 700; color: var(--primary); }

/* ── 报告Tab ── */
.report-layout { flex: 1; overflow-y: auto; padding: 24px; }

.report-header {
    display: flex; justify-content: space-between; align-items: center;
    margin-bottom: 24px;
}

.stat-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px; margin-bottom: 24px;
}

.stat-card {
    background: var(--card-bg); border-radius: var(--radius);
    padding: 20px; box-shadow: var(--shadow); text-align: center;
}

.stat-card .stat-value { font-size: 32px; font-weight: 700; color: var(--primary); }
.stat-card .stat-label { font-size: 13px; color: var(--text-secondary); margin-top: 4px; }

.concept-table {
    width: 100%; border-collapse: collapse;
    background: var(--card-bg); border-radius: var(--radius);
    overflow: hidden; box-shadow: var(--shadow);
}

.concept-table th {
    background: #F8FAFC; padding: 12px 16px;
    text-align: left; font-size: 13px; font-weight: 600;
    color: var(--text-secondary);
}

.concept-table td {
    padding: 12px 16px; font-size: 14px;
    border-top: 1px solid var(--border);
}

.status-badge {
    padding: 2px 10px; border-radius: 12px; font-size: 12px; font-weight: 500;
}

.status-weak { background: #FFF2F0; color: var(--danger); }
.status-learning { background: #FFFBE6; color: var(--warning); }
.status-mastered { background: #F6FFED; color: var(--success); }

/* ── 知识图谱Tab ── */
.graph-layout {
    flex: 1; overflow: auto; padding: 24px;
    display: flex; flex-direction: column; align-items: center;
}

#graphCanvas {
    background: var(--card-bg); border-radius: var(--radius);
    box-shadow: var(--shadow);
}

/* ── 滚动条 ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #CBD5E1; border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: #94A3B8; }

/* ── 响应式 ── */
@media (max-width: 768px) {
    .chat-sidebar { display: none; }
    .chat-message { max-width: 95%; }
    .stat-cards { grid-template-columns: 1fr 1fr; }
    .app-header h1 { font-size: 16px; }
}

/* ── 学期分组 ── */
.semester-group {
    margin-bottom: 8px;
}

.semester-header {
    padding: 8px 10px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 4px;
    border-radius: 6px;
    user-select: none;
}

.semester-header:hover {
    background: #F5F7FA;
    color: var(--primary);
}

.semester-arrow {
    font-size: 10px;
    transition: transform 0.2s;
    width: 12px;
}

.semester-count {
    font-size: 11px;
    color: #B0BEC5;
    margin-left: auto;
}

.semester-items {
    padding-left: 4px;
}

.semester-group.collapsed .semester-items {
    display: none;
}

.semester-group.collapsed .semester-arrow {
    transform: rotate(-90deg);
}