:root {
    --primary: #007AFF;
    --primary-dark: #0A84FF;
    --success: #34C759;
    --success-dark: #30D158;
    --warning: #FF9500;
    --warning-dark: #FF9F0A;
    --error: #FF3B30;
    --error-dark: #FF453A;
    --label: #000000;
    --secondary-label: #3C3C43;
    --bg: #FFFFFF;
    --surface: #F2F2F7;
    --card: #FFFFFF;
    --separator: #E5E5EA;
    --card-radius: 16px;
    --btn-radius: 12px;
    --input-radius: 10px;
    --blur-bg: rgba(255,255,255,0.72);
}

@media (prefers-color-scheme: dark) {
    :root {
        --primary: #0A84FF;
        --primary-dark: #409CFF;
        --success: #30D158;
        --success-dark: #63DB8B;
        --warning: #FF9F0A;
        --warning-dark: #FFD426;
        --error: #FF453A;
        --error-dark: #FF6961;
        --label: #FFFFFF;
        --secondary-label: #EBEBF5;
        --bg: #000000;
        --surface: #1C1C1E;
        --card: #1C1C1E;
        --separator: #38383A;
        --blur-bg: rgba(28,28,30,0.72);
    }
}

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

body {
    font-family: 'Segoe UI Variable', 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--label);
    min-height: 100vh;
    overflow-x: hidden;
}

/* 顶栏 */
.toolbar {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 24px;
    background: var(--blur-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--separator);
}

.toolbar-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.class-name {
    font-size: 22px;
    font-weight: 600;
}

.date-display {
    font-size: 15px;
    color: var(--secondary-label);
}

.toolbar-right {
    display: flex;
    gap: 8px;
}

.toolbar-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border: none;
    border-radius: var(--btn-radius);
    background: var(--surface);
    color: var(--label);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: transform 100ms ease, background 150ms ease;
}

.toolbar-btn:hover {
    background: var(--separator);
}

.toolbar-btn:active {
    transform: scale(0.97);
}

.toolbar-btn svg {
    width: 18px;
    height: 18px;
}

.btn-ai {
    background: var(--primary);
    color: #fff;
}

.btn-ai:hover {
    background: var(--primary-dark);
}

/* 管理区 */
.admin-bar {
    padding: 12px 24px;
}

.admin-btn {
    padding: 10px 24px;
    border: none;
    border-radius: var(--btn-radius);
    background: var(--surface);
    color: var(--label);
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: transform 100ms ease, background 150ms ease;
}

.admin-btn:hover {
    background: var(--separator);
}

.admin-btn:active {
    transform: scale(0.97);
}

/* 学生网格 */
.grid-container {
    padding: 16px 24px;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 12px;
}

.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 80px 20px;
    color: var(--secondary-label);
}

.empty-state p:first-child {
    font-size: 18px;
    margin-bottom: 8px;
}

/* 学生卡片 */
.student-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 16px 8px;
    background: var(--card);
    border: 1px solid var(--separator);
    border-radius: var(--card-radius);
    cursor: pointer;
    transition: transform 100ms ease, box-shadow 200ms ease;
    min-height: 80px;
    position: relative;
}

.student-card:hover {
    transform: scale(1.03);
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
}

.student-card:active {
    transform: scale(0.97);
}

.student-card .student-name {
    font-size: 16px;
    font-weight: 600;
    text-align: center;
    word-break: break-all;
}

.student-card .student-score {
    font-size: 13px;
    font-weight: 600;
    margin-top: 4px;
}

.student-card .student-score.positive {
    color: var(--success);
}

.student-card .student-score.negative {
    color: var(--error);
}

.student-card.absent {
    background: var(--warning);
    border-color: var(--warning);
    color: #fff;
}

.student-card.absent .student-name {
    color: #fff;
}

/* 弹窗 */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 200ms ease;
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: all;
}

.modal {
    background: var(--card);
    border-radius: var(--card-radius);
    box-shadow: 0 8px 32px rgba(0,0,0,0.16);
    width: 90%;
    max-width: 480px;
    max-height: 85vh;
    display: flex;
    flex-direction: column;
    transform: scale(0.92) translateY(20px);
    transition: transform 250ms cubic-bezier(0.42, 0, 0.58, 1);
    overflow: hidden;
}

.modal-overlay.active .modal {
    transform: scale(1) translateY(0);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px 12px;
}

.modal-title-row {
    display: flex;
    align-items: baseline;
    gap: 12px;
}

.modal-student-name {
    font-size: 24px;
    font-weight: 600;
}

.modal-daily-score {
    font-size: 18px;
    font-weight: 700;
}

.modal-daily-score.positive {
    color: var(--success);
}

.modal-daily-score.negative {
    color: var(--error);
}

.modal-close {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: 50%;
    background: var(--surface);
    color: var(--secondary-label);
    font-size: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 150ms ease;
}

.modal-close:hover {
    background: var(--separator);
}

.modal-body {
    flex: 1;
    overflow-y: auto;
    padding: 0 24px 16px;
}

.modal-actions-top {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.action-btn {
    padding: 8px 16px;
    border: none;
    border-radius: var(--btn-radius);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: transform 100ms ease, background 150ms ease;
}

.action-btn:active {
    transform: scale(0.97);
}

.btn-absent {
    background: var(--warning);
    color: #fff;
}

.btn-present {
    background: var(--success);
    color: #fff;
}

.btn-clear {
    background: var(--error);
    color: #fff;
}

.btn-clear:hover {
    background: var(--error-dark);
}

/* 记录列表 */
.modal-records h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--secondary-label);
    margin-bottom: 8px;
}

.records-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.no-records {
    text-align: center;
    color: var(--secondary-label);
    padding: 20px;
    font-size: 14px;
}

.record-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 12px;
    background: var(--surface);
    border-radius: var(--input-radius);
    font-size: 14px;
    cursor: pointer;
    transition: background 150ms ease;
}

.record-item:hover {
    background: var(--separator);
}

.record-seq {
    font-weight: 600;
    color: var(--secondary-label);
    min-width: 24px;
}

.record-desc {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.record-desc.expanded {
    white-space: normal;
    word-break: break-all;
}

.record-score {
    font-weight: 600;
    min-width: 30px;
    text-align: right;
}

.record-score.positive {
    color: var(--success);
}

.record-score.negative {
    color: var(--error);
}

.record-score.zero {
    color: var(--secondary-label);
}

.record-time {
    font-size: 12px;
    color: var(--secondary-label);
    min-width: 50px;
}

/* 表单 */
.modal-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--separator);
}

.new-record-form {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.record-input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--separator);
    border-radius: var(--input-radius);
    font-size: 15px;
    background: var(--surface);
    color: var(--label);
    outline: none;
    transition: border-color 150ms ease;
}

.record-input:focus {
    border-color: var(--primary);
}

.score-buttons {
    display: flex;
    gap: 6px;
    justify-content: center;
}

.score-btn {
    width: 44px;
    height: 44px;
    border: none;
    border-radius: var(--btn-radius);
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 100ms ease, background 150ms ease;
}

.score-btn:active {
    transform: scale(0.93);
}

.score-btn.negative {
    background: #FFEBE9;
    color: var(--error);
}

.score-btn.negative:hover {
    background: #FFD6D3;
}

.score-btn.neutral {
    background: var(--surface);
    color: var(--secondary-label);
}

.score-btn.neutral:hover {
    background: var(--separator);
}

.score-btn.positive {
    background: #E8F9ED;
    color: var(--success);
}

.score-btn.positive:hover {
    background: #D1F2D8;
}

@media (prefers-color-scheme: dark) {
    .score-btn.negative {
        background: rgba(255,69,58,0.15);
    }
    .score-btn.positive {
        background: rgba(48,209,88,0.15);
    }
}

.submit-btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--btn-radius);
    background: var(--primary);
    color: #fff;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 100ms ease, background 150ms ease;
}

.submit-btn:hover {
    background: var(--primary-dark);
}

.submit-btn:active {
    transform: scale(0.97);
}

/* 管理弹窗 */
.modal-admin,
.modal-import,
.modal-detail {
    max-width: 560px;
}

.admin-add-row {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
}

.admin-add-row .record-input {
    flex: 1;
}

.student-list-admin {
    max-height: 400px;
    overflow-y: auto;
}

.student-admin-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 12px;
    border-radius: var(--input-radius);
    transition: background 150ms ease;
}

.student-admin-item:hover {
    background: var(--surface);
}

.student-admin-item .name {
    font-size: 15px;
}

.student-admin-item .btns {
    display: flex;
    gap: 6px;
}

.student-admin-item .btns button {
    padding: 4px 10px;
    border: none;
    border-radius: 6px;
    font-size: 12px;
    cursor: pointer;
    transition: transform 100ms ease;
}

.student-admin-item .btns button:active {
    transform: scale(0.95);
}

.btn-edit {
    background: var(--surface);
    color: var(--label);
}

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

/* 导入弹窗 */
.import-dropzone {
    border: 2px dashed var(--separator);
    border-radius: var(--card-radius);
    padding: 48px 24px;
    text-align: center;
    color: var(--secondary-label);
    cursor: pointer;
    transition: border-color 150ms ease, background 150ms ease;
}

.import-dropzone:hover,
.import-dropzone.dragover {
    border-color: var(--primary);
    background: rgba(0,122,255,0.05);
}

.import-preview {
    margin-top: 16px;
}

.import-list {
    max-height: 200px;
    overflow-y: auto;
    margin: 12px 0;
    padding: 8px;
    background: var(--surface);
    border-radius: var(--input-radius);
}

.import-list p {
    padding: 4px 8px;
    font-size: 14px;
}

/* 详情弹窗 */
.detail-content {
    font-size: 15px;
    line-height: 1.6;
}

.detail-content .detail-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
}

.detail-content .detail-row {
    padding: 6px 0;
    border-bottom: 1px solid var(--separator);
}

.detail-content .detail-row:last-child {
    border-bottom: none;
}

.detail-content .detail-total {
    margin-top: 12px;
    font-weight: 600;
    font-size: 16px;
}

/* 响应式 */
@media (max-width: 768px) {
    .toolbar {
        flex-direction: column;
        gap: 8px;
    }
    .toolbar-right {
        flex-wrap: wrap;
        justify-content: center;
    }
    .grid-container {
        grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
        gap: 8px;
        padding: 12px;
    }
    .toolbar-btn span {
        display: none;
    }
    .modal {
        width: 95%;
    }
}

/* 减少动效 */
@media (prefers-reduced-motion: reduce) {
    .modal-overlay,
    .modal,
    .student-card,
    .toolbar-btn,
    .action-btn,
    .submit-btn,
    .score-btn {
        transition: none !important;
    }
}