.utm-section {
    --tool-accent: #6366F1;
    --tool-accent-rgb: 99, 102, 241;
}

/* Layout */
.utm-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    padding: 1.5rem;
}

.utm-form-col,
.utm-output-col {
    min-width: 0;
}

@media (max-width: 860px) {
    .utm-layout {
        grid-template-columns: 1fr;
    }
}

/* ── Platform presets ─────────────────────────────────────────────────── */
.utm-presets-section {
    margin-bottom: 1.25rem;
    padding-bottom: 1.1rem;
    border-bottom: 1px solid var(--tool-border);
}

.utm-presets-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--tool-text-muted);
    margin-bottom: 0.6rem;
}

.utm-preset-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.4rem;
}

.utm-preset-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.3rem;
    padding: 0.55rem 0.3rem;
    background: #FFFFFF;
    border: 1.5px solid var(--tool-border);
    border-radius: var(--tool-radius-md);
    cursor: pointer;
    font-family: inherit;
    transition: border-color 0.15s, background 0.15s;
}

.utm-preset-card:hover {
    border-color: rgba(var(--tool-accent-rgb), 0.45);
    background: rgba(var(--tool-accent-rgb), 0.03);
}

.utm-preset-card>i {
    font-size: 1.3rem;
    color: var(--tool-text-muted);
    transition: color 0.15s;
}

.utm-preset-card>span {
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--tool-text-muted);
    text-align: center;
    line-height: 1.2;
    white-space: nowrap;
}

.utm-preset-card--active {
    border-color: var(--tool-accent);
    background: rgba(var(--tool-accent-rgb), 0.06);
}

.utm-preset-card--active>i,
.utm-preset-card--active>span {
    color: var(--tool-accent);
}

.utm-preset-card--custom>i {
    color: var(--tool-text-muted);
}

@media (max-width: 540px) {
    .utm-preset-grid {
        grid-template-columns: repeat(5, 1fr);
    }
}

/* ── History section ─────────────────────────────────────────────────── */
.utm-history-section {
    margin-top: 1.25rem;
    margin-bottom: 1rem;
    border: 1px solid var(--tool-border);
    border-radius: var(--tool-radius-md);
    overflow: hidden;
}

.utm-history-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 0.65rem 0.9rem;
    background: var(--tool-surface);
    border: none;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--tool-text-primary);
    gap: 0.5rem;
    border-radius: var(--tool-radius-md) var(--tool-radius-md) 0 0;
    user-select: none;
}

.utm-history-toggle:hover {
    background: rgba(var(--tool-accent-rgb), 0.04);
}

.utm-history-toggle-left {
    display: flex;
    align-items: center;
    gap: 0.45rem;
}

.utm-history-toggle-left>i {
    font-size: 1rem;
    color: var(--tool-accent);
}

.utm-history-toggle-right {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.utm-history-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 18px;
    height: 18px;
    padding: 0 5px;
    background: var(--tool-accent);
    color: #fff;
    font-size: 0.7rem;
    font-weight: 700;
    border-radius: 50px;
}

.utm-history-caret {
    font-size: 0.9rem;
    color: var(--tool-text-muted);
    transition: transform 0.2s;
    flex-shrink: 0;
}

.utm-history-caret--open {
    transform: rotate(180deg);
}

.utm-history-panel {
    display: none;
    border-top: 1px solid var(--tool-border);
}

.utm-history-panel--open {
    display: block;
}

.utm-history-empty {
    padding: 0.75rem 0.9rem;
    font-size: 0.875rem;
    color: var(--tool-text-muted);
    margin: 0;
}

.utm-history-list {
    display: flex;
    flex-direction: column;
}

.utm-history-table-wrap {
    overflow-x: auto;
}

.utm-history-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
    table-layout: fixed;
}

.utm-history-table thead th {
    background: rgba(var(--tool-accent-rgb), 0.04);
    padding: 0.5rem 0.75rem;
    text-align: left;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--tool-accent);
    border-bottom: 1px solid rgba(var(--tool-accent-rgb), 0.15);
}

.utm-history-table thead th:last-child,
.utm-history-th-actions {
    text-align: right;
}

.utm-history-table tbody tr:not(:last-child) td {
    border-bottom: 1px solid var(--tool-border);
}

.utm-history-table tbody td {
    padding: 0.45rem 0.75rem;
    vertical-align: middle;
}

.utm-history-td-url {
    font-family: var(--tool-font-mono);
    font-size: 0.78rem;
    color: var(--tool-text-muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 0;
}

.utm-history-td-time {
    font-size: 0.75rem;
    color: var(--tool-text-muted);
    white-space: nowrap;
}

.utm-history-td-actions {
    display: flex;
    gap: 0.3rem;
    justify-content: flex-end;
}

/* Fields */
.utm-field-group {
    margin-bottom: 1rem;
}

.utm-label {
    display: flex;
    flex-direction: column;
    gap: 2px;
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--tool-text-primary);
    margin-bottom: 0.35rem;
}

.utm-required {
    color: var(--tool-accent);
    font-size: 0.9375rem;
}

.utm-hint {
    font-size: 0.8125rem;
    font-weight: 400;
    color: var(--tool-text-muted);
}

.utm-input {
    width: 100%;
}

/* Separator */
.utm-separator {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin: 1.25rem 0 1rem;
    color: var(--tool-text-muted);
    font-size: 0.9375rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.utm-separator::before,
.utm-separator::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--tool-border);
}

/* Output column */
.utm-output-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.75rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--tool-text-primary);
    flex-wrap: wrap;
    gap: 0.5rem;
}

.utm-output-actions {
    display: flex;
    gap: 0.5rem;
}

.utm-url-display {
    font-family: var(--tool-font-mono);
    font-size: 0.9375rem;
    padding: 0.9rem 1rem;
    border: 1px solid var(--tool-border);
    border-radius: var(--tool-radius-md);
    background: var(--tool-surface);
    min-height: 80px;
    word-break: break-all;
    line-height: 1.7;
    color: var(--tool-text-primary);
    margin-bottom: 1rem;
}

.utm-url-display .utm-placeholder {
    color: var(--tool-text-muted);
    font-family: var(--tool-font-sans, inherit);
    font-size: 0.9375rem;
}

.utm-url-display .utm-base {
    color: var(--tool-text-secondary);
}

.utm-url-display .utm-param {
    color: var(--tool-accent);
    font-weight: 600;
}

/* ── Params table (below QR) ─────────────────────────────────────────── */
.utm-params-table-section {
    margin-top: 1.25rem;
    border: 1px solid var(--tool-border);
    border-radius: var(--tool-radius-md);
    overflow: hidden;
}

.utm-params-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.utm-params-table thead th {
    background: var(--tool-surface);
    padding: 0.45rem 0.8rem;
    text-align: left;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--tool-text-muted);
    border-bottom: 1px solid var(--tool-border);
}

.utm-params-col-key {
    width: 38%;
}

.utm-params-table tbody tr:not(:last-child) td {
    border-bottom: 1px solid var(--tool-border);
}

.utm-params-table tbody td {
    padding: 0.45rem 0.8rem;
    vertical-align: middle;
}

.utm-params-table tbody td:first-child {
    font-family: var(--tool-font-mono);
    color: var(--tool-accent);
    font-size: 0.8125rem;
    font-weight: 600;
}

.utm-params-table tbody td:last-child {
    color: var(--tool-text-primary);
    font-size: 0.875rem;
    word-break: break-all;
}

/* Tips */
.utm-tips {
    padding: 0.85rem 1rem;
    border: 1px solid rgba(var(--tool-accent-rgb), 0.2);
    border-radius: var(--tool-radius-md);
    background: rgba(var(--tool-accent-rgb), 0.04);
}

.utm-tips-title {
    font-size: 0.9375rem;
    font-weight: 700;
    color: var(--tool-accent);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.utm-tips-list {
    margin: 0;
    padding-left: 1.25rem;
    font-size: 0.9375rem;
    color: var(--tool-text-secondary);
    line-height: 1.7;
}

.utm-tips-list li+li {
    margin-top: 0.2rem;
}

/* ── QR code section ─────────────────────────────────────────────────────── */
.utm-qr-section {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid rgba(139, 92, 246, 0.15);
}

.utm-qr-title {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--tool-text-secondary, #9ca3af);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 6px;
}

#utm-qr-canvas img,
#utm-qr-canvas canvas {
    border-radius: 8px;
    display: block;
}