* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Microsoft YaHei", Arial, sans-serif;
    color: #222222;
    background: #ffffff;
}

.page {
    width: min(960px, 94%);
    margin: 0 auto;
    padding: 24px 0;
}

.site-header {
    margin-bottom: 22px;
    padding: 18px 0 14px;
    color: #222222;
    background: #ffffff;
    border-bottom: 2px solid #333333;
}

.course {
    margin: 0 0 6px;
    font-size: 15px;
}

h1,
h2,
h3,
p {
    margin-top: 0;
}

h1 {
    margin-bottom: 0;
    font-size: 28px;
    font-weight: 700;
}

.student-info {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
    margin-top: 12px;
    font-size: 15px;
}

h2 {
    margin-bottom: 10px;
    padding-bottom: 6px;
    font-size: 21px;
    border-bottom: 1px solid #cccccc;
}

h3 {
    margin-bottom: 10px;
    font-size: 18px;
}

.intro {
    max-width: 720px;
    margin-bottom: 0;
    line-height: 1.8;
}

.experiment-section {
    margin-bottom: 24px;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

.two-card-grid {
    grid-template-columns: repeat(2, 1fr);
}

.card,
.content-card {
    padding: 16px;
    background: #ffffff;
    border: 1px solid #bbbbbb;
    border-radius: 0;
    box-shadow: none;
}

.card p {
    min-height: 58px;
    line-height: 1.7;
}

.tag {
    display: inline-block;
    margin-bottom: 10px;
    padding: 3px 8px;
    color: #333333;
    background: #eeeeee;
    border: 1px solid #cccccc;
    border-radius: 0;
    font-size: 14px;
}

.button,
button {
    display: inline-block;
    padding: 7px 14px;
    color: #ffffff;
    background: #333333;
    border: 0;
    border-radius: 0;
    font-size: 15px;
    text-decoration: none;
    cursor: pointer;
}

.button:hover,
button:hover {
    background: #555555;
}

.back-link {
    display: inline-block;
    margin-top: 24px;
    color: #003399;
    text-decoration: none;
}

.back-link:hover {
    text-decoration: underline;
}

.result-list {
    display: grid;
    gap: 10px;
    margin-top: 16px;
}

.result-item {
    padding: 12px 14px;
    background: #f7f7f7;
    border: 1px solid #cccccc;
    border-radius: 0;
}

.table-box {
    overflow-x: auto;
}

.table-row {
    display: flex;
    gap: 6px;
    margin-bottom: 6px;
    white-space: nowrap;
}

.table-cell {
    min-width: 72px;
    padding: 6px 8px;
    text-align: center;
    background: #f7f7f7;
    border: 1px solid #cccccc;
    border-radius: 0;
    font-size: 14px;
}

.form-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px;
}

input {
    width: 160px;
    padding: 9px 10px;
    border: 1px solid #999999;
    border-radius: 0;
    font-size: 15px;
}

select {
    padding: 8px 10px;
    border: 1px solid #999999;
    border-radius: 0;
    font-size: 15px;
    background: #ffffff;
}

.select-row,
.calculator-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px;
}

.operator {
    font-size: 20px;
    font-weight: 700;
}

.result-text {
    min-height: 28px;
    margin-top: 18px;
    margin-bottom: 0;
    font-weight: 700;
    color: #333333;
}

.error {
    color: #b3261e;
}

.object-list {
    display: grid;
    gap: 10px;
    margin-top: 16px;
}

.object-row {
    padding: 12px 14px;
    background: #f7f7f7;
    border: 1px solid #cccccc;
    border-radius: 0;
    line-height: 1.7;
}

.date-panel,
.clock-panel {
    margin-top: 18px;
    padding: 26px;
    text-align: center;
    background: #f7f7f7;
    border: 1px solid #cccccc;
    border-radius: 0;
}

.date-text {
    margin-bottom: 0;
    font-size: 24px;
    font-weight: 700;
}

.clock-title {
    margin-bottom: 8px;
    font-size: 24px;
    font-weight: 700;
}

.clock-time {
    font-size: 40px;
    font-weight: 700;
    letter-spacing: 0;
}

@media (max-width: 760px) {
    .card-grid {
        grid-template-columns: 1fr;
    }

    .site-header {
        padding: 22px;
    }

    h1 {
        font-size: 24px;
    }

    .date-text {
        font-size: 20px;
    }

    .clock-time {
        font-size: 32px;
    }
}