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

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #f1f5f9;
    color: #111827;
}

.page {
    max-width: 1000px;
    margin: auto;
    padding: 20px;
}

.hero-section {
    text-align: center;
    margin-bottom: 24px;
}

.hero-section h1 {
    font-size: 36px;
    margin-bottom: 8px;
}

.hero-section p {
    color: #64748b;
    font-size: 14px;
}

.main-layout {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 20px;
}

.calculator-card,
.result-card,
.details-card,
.history-card {
    background: white;
    border-radius: 18px;
    padding: 20px;
    border: 1px solid #e5e7eb;
}

.details-card,
.history-card {
    grid-column: 1 / 3;
}

.card-heading {
    display: flex;
    justify-content: space-between;
    margin-bottom: 18px;
}

.card-heading span {
    background: #eef2ff;
    color: #4338ca;
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 12px;
}

.date-grid,
.details-grid {
    display: grid;
    gap: 14px;
}

.date-grid {
    grid-template-columns: 1fr 1fr;
}

.details-grid {
    grid-template-columns: repeat(3, 1fr);
    margin-top: 16px;
}

.date-box {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.date-box input {
    padding: 12px;
    border-radius: 12px;
    border: 1px solid #cbd5e1;
    background: #f8fafc;
}

.date-box input:focus {
    border-color: #4f46e5;
    background: white;
    outline: none;
}

.option-row {
    margin-top: 16px;
}

.option-row label {
    display: flex;
    gap: 10px;
    font-size: 14px;
}

.button-row {
    display: flex;
    gap: 12px;
    margin-top: 18px;
}

button {
    border: none;
    padding: 12px;
    border-radius: 12px;
    cursor: pointer;
    transition: 0.2s ease;
}

button:hover {
    transform: translateY(-1px);
    opacity: 0.95;
}

#calculateBtn {
    flex: 1;
    background: #4f46e5;
    color: white;
}

#clearBtn {
    background: #e5e7eb;
}

.quick-tools {
    display: flex;
    gap: 10px;
    margin-top: 14px;
    flex-wrap: wrap;
}

.quick-btn {
    background: #eef2ff;
    color: #4338ca;
    padding: 10px 14px;
    font-size: 13px;
}

.message-box {
    margin-top: 18px;
    background: #eef2ff;
    color: #4338ca;
    padding: 12px;
    border-radius: 12px;
    font-size: 14px;
}

.main-result {
    background: #4f46e5;
    color: white;
    border-radius: 18px;
    padding: 24px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.main-result::before {
    content: "";
    position: absolute;
    width: 120px;
    height: 120px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 50%;
    top: -40px;
    right: -30px;
}

.main-result strong {
    display: block;
    font-size: 48px;
    margin: 10px 0;
}

.mini-result-grid,
.history-list {
    display: grid;
    gap: 12px;
    margin-top: 16px;
}

.mini-result,
.detail-box,
.history-item,
.empty-history {
    background: #f8fafc;
    border: 1px solid #e5e7eb;
    border-radius: 14px;
    padding: 16px;
}

.mini-result span,
.detail-box span,
.history-item span {
    display: block;
    color: #64748b;
    font-size: 13px;
    margin-bottom: 6px;
}

.detail-box strong {
    font-size: 18px;
    line-height: 1.4;
}

.history-item strong {
    display: block;
    margin-bottom: 6px;
}

.empty-history {
    text-align: center;
    color: #64748b;
}

@media (max-width: 800px) {
    .main-layout,
    .date-grid,
    .details-grid {
        grid-template-columns: 1fr;
    }

    .details-card,
    .history-card {
        grid-column: auto;
    }

    .button-row {
        flex-direction: column;
    }
}