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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    /* 背景由 JS 动态设置 */
    position: relative;
}

/* 背景遮罩层，让文字更清晰 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.3);
    z-index: -1;
}

.container {
    width: 100%;
    max-width: 1200px;
    padding: 20px;
}

.page {
    animation: fadeIn 0.3s;
}

.hidden {
    display: none !important;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 登录页面 - 液态玻璃效果 */
.login-box {
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3), 
                inset 0 1px 0 rgba(255, 255, 255, 0.3);
    max-width: 400px;
    margin: 0 auto;
}

.login-box h1 {
    text-align: center;
    color: #ffffff;
    margin-bottom: 10px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    font-weight: 600;
}

.subtitle {
    text-align: center;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 30px;
    text-shadow: 0 1px 5px rgba(0, 0, 0, 0.2);
}

#loginForm input {
    width: 100%;
    padding: 12px 16px;
    margin-bottom: 15px;
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    font-size: 14px;
    color: #ffffff;
    transition: all 0.3s;
}

#loginForm input::placeholder {
    color: rgba(255, 255, 255, 0.7);
}

#loginForm input:focus {
    outline: none;
    background: rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.4);
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.1);
}

#loginForm button {
    width: 100%;
    padding: 12px;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.4);
}

#loginForm button:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 255, 255, 0.3);
    border-color: rgba(255, 255, 255, 0.5);
}

.error {
    color: #ffffff;
    text-align: center;
    margin-top: 10px;
    font-size: 14px;
    background: rgba(255, 107, 107, 0.25);
    padding: 10px;
    border-radius: 8px;
    border: 1px solid rgba(255, 107, 107, 0.4);
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

.error:empty {
    display: none;
    padding: 0;
    margin: 0;
}

/* 主页面 - 液态玻璃效果 */
#mainPage {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 20px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3),
                inset 0 1px 0 rgba(255, 255, 255, 0.25);
    overflow: hidden;
}

header {
    background: rgba(255, 255, 255, 0.08);
    border-bottom: 1px solid rgba(255, 255, 255, 0.15);
    color: white;
    padding: 20px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    font-size: 24px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

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

#logoutBtn {
    padding: 8px 16px;
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
}

#logoutBtn:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(255, 255, 255, 0.2);
}

/* 标签页 */
.tabs {
    display: flex;
    background: rgba(255, 255, 255, 0.05);
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.tab-btn {
    flex: 1;
    padding: 15px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 16px;
    color: rgba(255, 255, 255, 0.7);
    transition: all 0.3s;
}

.tab-btn.active {
    background: rgba(255, 255, 255, 0.12);
    color: #ffffff;
    border-bottom: 2px solid rgba(255, 255, 255, 0.6);
    text-shadow: 0 1px 5px rgba(0, 0, 0, 0.2);
}

.tab-content {
    padding: 30px;
    min-height: 500px;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.section-header h2 {
    color: #ffffff;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.section-header button {
    padding: 8px 16px;
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
}

.section-header button:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(255, 255, 255, 0.2);
}

/* 考试列表 */
.exams-list {
    display: grid;
    gap: 15px;
}

.exam-card {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 12px;
    padding: 20px;
    border-left: 3px solid rgba(255, 255, 255, 0.4);
    transition: all 0.3s;
}

.exam-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.25);
}

.exam-card.urgent {
    border-left-color: rgba(255, 107, 107, 0.7);
    background: rgba(255, 107, 107, 0.12);
}

.exam-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 10px;
}

.exam-title {
    font-size: 18px;
    font-weight: bold;
    color: #ffffff;
    text-shadow: 0 1px 5px rgba(0, 0, 0, 0.3);
}

.days-badge {
    padding: 4px 12px;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
}

.days-badge.urgent {
    background: rgba(255, 107, 107, 0.3);
    border-color: rgba(255, 107, 107, 0.5);
}

.exam-details {
    color: rgba(255, 255, 255, 0.9);
    line-height: 1.8;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

.exam-details div {
    display: flex;
    gap: 10px;
}

.loading {
    text-align: center;
    padding: 40px;
    color: rgba(255, 255, 255, 0.7);
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

.placeholder {
    text-align: center;
    padding: 40px;
    color: rgba(255, 255, 255, 0.7);
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

/* 文件列表 */
.files-list {
    display: grid;
    gap: 12px;
}

.file-card {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 12px;
    padding: 16px 20px;
    display: flex;
    align-items: center;
    gap: 15px;
    transition: all 0.3s;
}

.file-card:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateX(5px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.file-icon {
    font-size: 32px;
    flex-shrink: 0;
}

.file-info {
    flex: 1;
    min-width: 0;
}

.file-name {
    color: #ffffff;
    font-weight: 500;
    margin-bottom: 4px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

.file-meta {
    color: rgba(255, 255, 255, 0.7);
    font-size: 13px;
    display: flex;
    gap: 8px;
}

.download-btn {
    padding: 8px 20px;
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 14px;
    flex-shrink: 0;
}

.download-btn:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.2);
}

/* 成绩统计 */
.grade-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    margin-bottom: 25px;
}

.stat-card {
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 12px;
    padding: 20px;
    text-align: center;
    transition: all 0.3s;
}

.stat-card:hover {
    background: rgba(255, 255, 255, 0.18);
    transform: translateY(-3px);
}

.stat-label {
    color: rgba(255, 255, 255, 0.8);
    font-size: 13px;
    margin-bottom: 8px;
}

.stat-value {
    color: #ffffff;
    font-size: 28px;
    font-weight: bold;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

/* 成绩列表 */
.grades-list {
    display: grid;
    gap: 12px;
}

.grade-card {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 12px;
    padding: 18px 20px;
    border-left: 4px solid rgba(102, 187, 106, 0.7);
    transition: all 0.3s;
}

.grade-card.fail {
    border-left-color: rgba(255, 107, 107, 0.7);
}

.grade-card:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateX(5px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.grade-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.grade-course {
    color: #ffffff;
    font-size: 16px;
    font-weight: 600;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

.grade-score {
    font-size: 24px;
    font-weight: bold;
    text-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
}

.grade-score.pass {
    color: #66bb6a;
}

.grade-score.fail {
    color: #ff6b6b;
}

.grade-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 8px;
    color: rgba(255, 255, 255, 0.85);
    font-size: 14px;
    line-height: 1.6;
}

.grade-details strong {
    color: rgba(255, 255, 255, 0.95);
}