:root {
    --bg: #f5f7fa;
    --card: #ffffff;
    --primary: #1e40af;
    --primary-light: #dbeafe;
    --accent-up: #dc2626;      /* 红: 上偏差 / 涨 */
    --accent-up-bg: #fef2f2;
    --accent-down: #16a34a;    /* 绿: 下偏差 / 跌 */
    --accent-down-bg: #f0fdf4;
    --text: #0f172a;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --shadow: 0 1px 3px rgba(15,23,42,0.06), 0 1px 2px rgba(15,23,42,0.04);
    --shadow-md: 0 4px 12px rgba(15,23,42,0.08), 0 2px 4px rgba(15,23,42,0.04);
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    font-size: 14px;
    line-height: 1.6;
}

.app {
    max-width: 1100px;
    margin: 0 auto;
    padding: 24px 20px 40px;
}

.header {
    text-align: center;
    margin-bottom: 24px;
    background: var(--primary);
    color: white;
    padding: 20px 24px;
    border-radius: 10px;
    box-shadow: var(--shadow-md);
}
.header h1 {
    margin: 0;
    font-size: 24px;
    font-weight: 600;
    color: white;
    letter-spacing: 0.5px;
}
.subtitle {
    margin-top: 6px;
    font-size: 13px;
    color: rgba(255,255,255,0.85);
}

/* Tabs */
.tab-bar {
    display: flex;
    gap: 4px;
    background: var(--card);
    padding: 6px;
    border-radius: 10px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
}
.tab-btn {
    flex: 1;
    padding: 10px 16px;
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-size: 14px;
    font-weight: 500;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.15s;
    font-family: inherit;
}
.tab-btn:hover {
    color: var(--primary);
    background: var(--primary-light);
}
.tab-btn.active {
    color: white;
    background: var(--primary);
    box-shadow: 0 1px 2px rgba(30,64,175,0.4);
}
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* Cards */
.card {
    background: var(--card);
    border-radius: 10px;
    padding: 20px 24px;
    box-shadow: var(--shadow);
    margin-bottom: 16px;
}
.card-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 14px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

/* Form */
.form-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-bottom: 14px;
}
@media (max-width: 700px) {
    .form-row { grid-template-columns: 1fr; }
}
.form-group label {
    display: block;
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 6px;
    font-weight: 500;
}
.form-group input, .form-group select {
    width: 100%;
    padding: 9px 12px;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 14px;
    font-family: inherit;
    background: white;
    color: var(--text);
    transition: border-color 0.15s, box-shadow 0.15s;
}
.form-group input:focus, .form-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(30,64,175,0.1);
}

/* Quick chips */
.quick-row {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 6px;
    padding-top: 6px;
}
.quick-label {
    font-size: 12px;
    color: var(--text-muted);
    margin-right: 4px;
}
.chip {
    padding: 5px 12px;
    background: var(--primary-light);
    color: var(--primary);
    border: 1px solid transparent;
    border-radius: 14px;
    font-size: 12px;
    font-family: "JetBrains Mono", "Consolas", monospace;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.15s;
}
.chip:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-1px);
}

/* Result */
.result-card {
    background: var(--card);
    border-radius: 10px;
    padding: 24px;
    box-shadow: var(--shadow-md);
    margin-top: 16px;
    animation: slideIn 0.25s ease-out;
}
@keyframes slideIn {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}
.result-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 20px;
}
.result-code {
    font-size: 44px;
    font-weight: 700;
    color: var(--primary);
    font-family: "JetBrains Mono", "Consolas", monospace;
}
.result-dim {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* Deviation table (红绿大数字) */
.deviation-table {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 24px;
}
@media (max-width: 700px) {
    .deviation-table { grid-template-columns: 1fr; }
}
.deviation-box {
    padding: 18px 20px;
    border-radius: 8px;
    border-left: 4px solid;
    position: relative;
}
.deviation-box.upper,
.deviation-box.lower {
    background: #f8fafc;
    border-left-color: var(--border);
}
.deviation-box.positive {
    background: var(--accent-down-bg);
    border-left-color: var(--accent-down);
}
.deviation-box.negative {
    background: var(--accent-up-bg);
    border-left-color: var(--accent-up);
}
.deviation-label {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 6px;
}
.deviation-value {
    font-size: 28px;
    font-weight: 700;
    font-family: "JetBrains Mono", "Consolas", monospace;
    line-height: 1.2;
}
.deviation-value.positive { color: var(--accent-down); }
.deviation-value.negative { color: var(--accent-up); }
.deviation-sub {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* Tolerance band SVG */
.tolerance-band {
    margin: 24px 0;
    padding: 16px 0;
}
.band-title {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 10px;
}
.band-svg {
    width: 100%;
    height: auto;
    display: block;
}
.band-info {
    display: flex;
    justify-content: space-between;
    margin-top: 8px;
    font-size: 16px;
    color: var(--text-muted);
    font-family: monospace;
}

/* Dim table */
.dim-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 12px;
    font-size: 13px;
}
.dim-table th, .dim-table td {
    padding: 10px 14px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}
.dim-table th {
    background: #f8fafc;
    font-weight: 600;
    color: var(--text-muted);
    font-size: 12px;
}
.dim-table td {
    font-family: "JetBrains Mono", "Consolas", monospace;
}
.dim-table .highlight {
    color: var(--primary);
    font-weight: 600;
}

/* Fit result */
.fit-summary {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 24px;
}
.fit-summary-box {
    padding: 16px 20px;
    border-radius: 8px;
    background: #f8fafc;
    border: 1px solid var(--border);
}
.fit-summary-box.positive {
    background: var(--accent-down-bg);
    border-color: var(--accent-down);
}
.fit-summary-box.negative {
    background: var(--accent-up-bg);
    border-color: var(--accent-up);
}
.fit-summary-box .label {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 4px;
}
.fit-summary-box .value {
    font-size: 22px;
    font-family: "JetBrains Mono", monospace;
    font-weight: 700;
}
.fit-summary-box .value.positive { color: var(--accent-down); }
.fit-summary-box .value.negative { color: var(--accent-up); }
.fit-summary-box .sub {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 2px;
}
.fit-badge {
    display: inline-block;
    padding: 8px 18px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 6px;
    margin-bottom: 4px;
}
.fit-badge.clearance { background: var(--accent-down-bg); color: var(--accent-down); border: 1px solid var(--accent-down); }
.fit-badge.transition { background: #fef3c7; color: #b45309; border: 1px solid #b45309; }
.fit-badge.interference { background: var(--accent-up-bg); color: var(--accent-up); border: 1px solid var(--accent-up); }

/* Data tables (IT) */
.table-wrap {
    overflow-x: auto;
    margin: 8px 0 4px;
}
.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 12px;
    font-family: "JetBrains Mono", "Consolas", monospace;
}
.data-table th, .data-table td {
    padding: 7px 10px;
    border: 1px solid var(--border);
    text-align: center;
}
.data-table th {
    background: var(--primary-light);
    color: var(--primary);
    font-weight: 600;
}
.data-table tbody tr:nth-child(even) {
    background: #f8fafc;
}

/* Empty hint */
.empty-hint {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
    font-size: 14px;
}
.empty-hint > div:last-child {
    margin-top: 8px;
}

/* Error */
.error-banner {
    background: var(--accent-up-bg);
    color: var(--accent-up);
    padding: 12px 16px;
    border-left: 4px solid var(--accent-up);
    border-radius: 6px;
    margin-top: 12px;
    font-size: 13px;
}

/* Footer */
.footer {
    text-align: center;
    margin-top: 32px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 12px;
}