/* 全局样式 - Minimalist Zen */
:root {
    --bg: #ffffff;
    --text-main: #171717;
    --text-muted: #737373;
    --border: #e5e5e5;
    --accent: #000000;
    --success: #16a34a;
    --error: #dc2626;
    --warning: #d97706;
    --hover: #f5f5f5;
    --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* 暗黑模式 */
.dark-mode {
    --bg: #171717;
    --text-main: #ffffff;
    --text-muted: #a3a3a3;
    --border: #404040;
    --accent: #ffffff;
    --success: #22c55e;
    --error: #ef4444;
    --warning: #f59e0b;
    --hover: #262626;
}

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

html {
    overflow-y: scroll;
}

body {
    font-family: var(--font-stack);
    background-color: var(--bg);
    color: var(--text-main);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

#quiz-container {
    max-width: 720px;
    width: 100%;
    margin: 2rem auto;
    padding: 2rem;
    position: relative;
    z-index: 1;
}

/* 进度条 */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--border);
    z-index: 1000;
}
.progress-fill {
    height: 100%;
    background: var(--accent);
    width: 0%;
    transition: width 0.3s ease;
}

/* 基础组件 */
.btn {
    display: inline-block;
    padding: 0.75rem 2.5rem;
    border: 1px solid var(--accent);
    background: transparent;
    color: var(--accent);
    text-transform: uppercase;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.15em;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    outline: none;
    border-radius: 0; /* 确保无圆角 */
}

.btn:hover {
    background: var(--accent);
    color: var(--bg);
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.65rem;
}

/* 统一所有原生按钮和特定功能按钮 */
button:not(.filter-item):not(.rating-btn), 
input[type="button"], 
input[type="submit"] {
    display: inline-block;
    padding: 0.75rem 2.5rem;
    border: 1px solid var(--accent);
    background: transparent;
    color: var(--accent);
    text-transform: uppercase;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.15em;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    outline: none;
    border-radius: 0;
}

button:not(.filter-item):not(.rating-btn):hover,
input[type="button"]:hover,
input[type="submit"]:hover {
    background: var(--accent);
    color: var(--bg);
}

/* 列表项样式 */
.list-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 0;
    border-bottom: 1px solid var(--border);
    text-decoration: none;
    color: inherit;
    transition: background 0.2s;
    cursor: pointer;
}
.list-item:hover {
    background: var(--hover);
    padding-left: 0.5rem;
}
.list-info .title {
    font-weight: 600;
    font-size: 1rem;
    display: block;
}
.list-info .sub {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* 测验头部 */
#quiz-header {
    text-align: center;
    margin-bottom: 3rem;
}
#quiz-title {
    font-weight: 200;
    font-size: 3rem;
    color: var(--text-main);
    margin-bottom: 0.5rem;
    letter-spacing: 0.05em;
}
#quiz-description {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

/* 计时器和得分 */
#quiz-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
}
#timer, #score {
    font-size: 1.2rem;
}
#time-display {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-muted);
    font-variant-numeric: tabular-nums;
}
#score-display {
    color: var(--text-muted);
}

/* 输入区域 */
#input-section {
    margin-bottom: 4rem;
    text-align: center;
}
#answer-input {
    width: 100%;
    border: none;
    border-bottom: 1px solid var(--text-main);
    padding: 1rem 0;
    font-size: 2.5rem;
    text-align: center;
    outline: none;
    background: transparent;
    font-family: inherit;
    transition: border-color 0.2s;
}
#answer-input::placeholder {
    color: var(--border);
}
#answer-input:focus {
    border-bottom-color: var(--accent);
}

.give-up-btn {
    margin-top: 2rem;
    border-color: var(--error);
    color: var(--error);
}
.give-up-btn:hover {
    background: var(--error);
    color: white;
}

/* 提示按钮样式 */
#hint-btn {
    margin-top: 2rem;
    border-color: var(--warning);
    color: var(--warning);
}

#hint-btn:hover {
    background: var(--warning);
    color: white;
}

#hint-btn:disabled {
    border-color: var(--border);
    color: var(--text-muted);
    cursor: not-allowed;
}

/* 答案网格 */
#answers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 1rem;
    margin-top: 2rem;
}
.answer-item {
    font-size: 0.85rem;
    padding: 0.5rem;
    color: var(--border);
    text-align: center;
    transition: color 0.2s;
    border: 1px solid var(--border);
    min-height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}
.answer-item.found {
    color: var(--text-main);
    font-weight: 600;
    background: transparent;
    box-shadow: none;
    transform: none;
}

/* 答案内容和注释上下排列 */
.answer-item {
    flex-direction: column;
    gap: 0.25rem;
}

.answer-item .answer-content {
    display: block;
    word-break: break-word;
    font-weight: 600;
}

.answer-item .answer-required {
    color: var(--text-main);
    font-weight: 600;
    background: linear-gradient(transparent 48%, #fff0a8 48%);
}

.answer-item .answer-context {
    color: var(--text-muted);
    font-weight: 400;
}

.dark-mode .answer-item .answer-required {
    background: linear-gradient(transparent 48%, #6b4f00 48%);
}

.answer-item.missed .answer-required {
    color: var(--error);
    background: linear-gradient(transparent 48%, rgba(220, 38, 38, 0.18) 48%);
}

.answer-item .answer-part-placeholder {
    display: block;
    min-width: 4rem;
    color: var(--border);
    letter-spacing: 0.08rem;
}

.answer-item .answer-comment {
    display: block;
    color: var(--text-muted);
    font-size: 0.75rem;
    font-weight: 400;
    word-break: break-word;
}

.answer-item.missed {
    color: var(--error);
    font-weight: 600;
    border-bottom: 1px dotted var(--error);
}

/* 结果面板 */
#results-panel {
    text-align: center;
    padding: 2rem 0;
}
#results-panel h2 {
    font-weight: 200;
    font-size: 3rem;
    margin-bottom: 1rem;
}

/* 筛选器 */
.filter-bar {
    margin-bottom: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}
.filter-row {
    display: flex;
    gap: 1.5rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 0.5rem;
}
.filter-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    font-weight: 700;
    width: 3rem;
    text-transform: uppercase;
}
.filter-item {
    font-size: 0.7rem;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0 0.2rem;
    transition: all 0.2s;
}
.filter-item.active {
    color: var(--text-main);
    border-bottom: 1px solid var(--accent);
}

/* 首页统计 */
.home-hero {
    text-align: center;
    padding: 4rem 0 3rem;
    margin-bottom: 2rem;
}
.home-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 3rem 0;
    flex-wrap: wrap;
}
.stat-box {
    text-align: center;
    min-width: 100px;
    padding: 1rem;
    border: 1px solid var(--border);
}
.stat-num {
    font-size: 2.5rem;
    font-weight: 200;
    display: block;
    line-height: 1;
}
.stat-label {
    font-size: 0.6rem;
    text-transform: uppercase;
    color: var(--text-muted);
    letter-spacing: 0.1em;
    margin-top: 0.5rem;
}

/* 批量操作工具栏 */
.bulk-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--hover);
    margin-bottom: 1rem;
    font-size: 0.75rem;
}

/* 复习模式评级面板 */
.rating-panel {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg);
    border-top: 1px solid var(--border);
    padding: 2rem;
    display: flex;
    justify-content: center;
    gap: 1rem;
    z-index: 100;
}
.rating-btn {
    flex: 1;
    max-width: 120px;
    padding: 1rem;
    text-align: center;
    border: 1px solid var(--border);
    cursor: pointer;
    transition: all 0.2s;
}
.rating-btn:hover { background: var(--hover); border-color: var(--accent); }
.rating-btn .interval { display: block; font-size: 0.6rem; color: var(--text-muted); margin-top: 0.4rem; }

/* 表单样式 */
.form-group {
    margin-bottom: 1.5rem;
}
.form-label {
    display: block;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
}
.form-input {
    width: 100%;
    border: 1px solid var(--border);
    padding: 0.75rem;
    font-family: inherit;
    outline: none;
    transition: border-color 0.2s;
}
.form-input:focus {
    border-color: var(--accent);
}

/* 动画 */
.fade-in {
    animation: fadeIn 0.4s ease-out;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 填空题样式 */
#fill-blank-section {
    margin-top: 30px;
}

.fill-blank-question {
    padding: 0;
    font-size: 1.2em;
    line-height: 1.8;
    color: var(--text-main);
    background: transparent;
    border-radius: 0;
}

.fill-blank-placeholder {
    display: inline;
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
    vertical-align: baseline;
    position: relative;
    white-space: nowrap;
}

/* 未作答的占位样式 - 灰色下划线 */
.fill-blank-placeholder.empty {
    background: transparent;
    border: none;
    border-bottom: 1px solid var(--border);
    border-radius: 0;
    padding: 0 4px;
    color: transparent;
    min-width: 2em;
    display: inline-block;
}

/* 已作答样式 - 文字加下划线，无框 */
.fill-blank-placeholder.filled {
    background: transparent;
    color: var(--text-main);
    border: none;
    border-bottom: 1px solid var(--accent);
    border-radius: 0;
    padding: 0 4px;
    display: inline;
}

/* 未答出样式 - 红色下划线 */
.fill-blank-placeholder.missed {
    background: transparent;
    color: var(--error);
    border: none;
    border-bottom: 1px solid var(--error);
    border-radius: 0;
    padding: 0 4px;
    display: inline;
}

.fill-blank-placeholder:hover {
    border-color: var(--text-muted);
}

.fill-blank-placeholder.filled:hover {
    background: var(--accent);
    border-color: var(--accent);
}

.fill-blank-placeholder.missed:hover {
    background: var(--error);
    border-color: var(--error);
}

/* 分组答题模式样式 */
.group-progress {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    padding: 15px 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.group-progress-info {
    display: flex;
    align-items: center;
    gap: 15px;
}

.group-progress-info span:first-child {
    font-weight: bold;
    font-size: 1.1em;
}

.current-quiz-name {
    background: rgba(255, 255, 255, 0.2);
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9em;
}

.group-nav-hint {
    background: rgba(255, 255, 255, 0.2);
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9em;
}

/* 分组结果汇总 */
.group-results-summary {
    margin-top: 20px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 10px;
}

.group-results-summary h3 {
    color: #48bb78;
    margin-bottom: 15px;
}

.group-result-item {
    display: flex;
    justify-content: space-between;
    padding: 10px 15px;
    background: white;
    border-radius: 8px;
    margin-bottom: 10px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.group-result-item .quiz-name {
    color: #333;
    font-weight: 500;
}

.group-result-item .quiz-score {
    color: #48bb78;
    font-weight: bold;
}

/* 分组模式下的导航提示 */
.group-nav-arrows {
    position: fixed;
    bottom: 50%;
    transform: translateY(50%);
    font-size: 3em;
    color: #667eea;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
}

.group-mode:hover .group-nav-arrows {
    opacity: 0.5;
}

.nav-arrow-left {
    left: 20px;
}

.nav-arrow-right {
    right: 20px;
}

/* 结算界面 - 内嵌式布局 */
.results-embedded {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    animation: fadeIn 0.4s ease-out;
}

.results-title {
    font-size: 1.5rem;
    font-weight: 200;
    letter-spacing: 0.3em;
    color: var(--text-main);
    margin-bottom: 2rem;
    text-align: center;
}

.results-stats {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    min-width: 100px;
    padding: 1.25rem 1rem;
    border: 1px solid var(--border);
    text-align: center;
    background: var(--bg);
}

.stat-card .stat-value {
    display: block;
    font-size: 2rem;
    font-weight: 200;
    color: var(--text-main);
    line-height: 1;
    margin-bottom: 0.5rem;
}

.stat-card .stat-label {
    font-size: 0.65rem;
    color: var(--text-muted);
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.results-divider {
    width: 100%;
    height: 1px;
    background: var(--border);
    margin: 2rem 0;
}

/* 未答出区域 */
.missed-section {
    margin-bottom: 2rem;
}

.missed-title {
    font-size: 0.7rem;
    letter-spacing: 0.15em;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-bottom: 1rem;
    text-align: center;
}

.missed-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.missed-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.875rem 1rem;
    border: 1px solid var(--error);
    font-size: 0.85rem;
    color: var(--error);
}

.missed-item .missed-comment {
    color: var(--text-muted);
    font-size: 0.75rem;
    font-style: italic;
}

/* 全部答对 */
.perfect-section {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    padding: 1.5rem;
    margin-bottom: 2rem;
    border: 1px solid var(--success);
    color: var(--success);
}

.perfect-icon {
    font-size: 1.2rem;
    font-weight: 600;
}

.perfect-text {
    font-size: 0.85rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
}

/* 操作按钮 */
.results-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.results-actions .btn {
    min-width: 120px;
}

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

.btn-primary:hover {
    background: transparent;
    color: var(--accent);
}

.btn-secondary {
    border-color: var(--text-muted);
    color: var(--text-muted);
}

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: transparent;
}