/* TSV to CSV - mobile-first, unique layout */
:root {
    --t2c-bg: #fafbfc;
    --t2c-surface: #ffffff;
    --t2c-border: #e6e9ef;
    --t2c-border-focus: #2563eb;
    --t2c-text: #1a1d24;
    --t2c-muted: #6b7280;
    --t2c-primary: #2563eb;
    --t2c-primary-hover: #1d4ed8;
    --t2c-success: #059669;
    --t2c-error: #dc2626;
    --t2c-radius: 10px;
    --t2c-radius-sm: 6px;
    --t2c-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
    --t2c-shadow-focus: 0 0 0 3px rgba(37, 99, 235, 0.2);
}

.t2c-tool {
    margin-bottom: 2rem;
}

/* Full-width card */
.t2c-card {
    width: 100%;
    background: var(--t2c-surface);
    border: 1px solid var(--t2c-border);
    border-radius: var(--t2c-radius);
    box-shadow: var(--t2c-shadow);
    overflow: hidden;
}

.t2c-card-bar {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding: 1rem;
    background: var(--t2c-bg);
    border-bottom: 1px solid var(--t2c-border);
}

.t2c-card-body {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding: 1rem;
}

.t2c-panel {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    min-height: 0;
}

.t2c-label {
    font-size: 0.8125rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    color: var(--t2c-muted);
}

.t2c-textarea {
    width: 100%;
    min-height: 160px;
    padding: 0.875rem 1rem;
    font-size: 0.875rem;
    line-height: 1.55;
    color: var(--t2c-text);
    background: var(--t2c-surface);
    border: 1px solid var(--t2c-border);
    border-radius: var(--t2c-radius);
    box-shadow: var(--t2c-shadow);
    resize: vertical;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.t2c-textarea::placeholder {
    color: var(--t2c-muted);
    opacity: 0.9;
}

.t2c-textarea:focus {
    outline: none;
    border-color: var(--t2c-border-focus);
    box-shadow: var(--t2c-shadow-focus);
}

.t2c-textarea-output {
    background: var(--t2c-bg);
    cursor: default;
    min-height: 140px;
}

.t2c-panel .t2c-textarea {
    flex: 1;
    min-height: 200px;
}

.t2c-options {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.75rem 1.25rem;
}

.t2c-option {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.t2c-option-label {
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--t2c-muted);
    white-space: nowrap;
}

.t2c-select {
    padding: 0.5rem 0.75rem;
    font-size: 0.875rem;
    color: var(--t2c-text);
    background: var(--t2c-bg);
    border: 1px solid var(--t2c-border);
    border-radius: var(--t2c-radius-sm);
    cursor: pointer;
    transition: border-color 0.2s ease;
}

.t2c-select:focus {
    outline: none;
    border-color: var(--t2c-border-focus);
}

.t2c-check {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8125rem;
    color: var(--t2c-muted);
    cursor: pointer;
    user-select: none;
}

.t2c-check input {
    width: 1rem;
    height: 1rem;
    accent-color: var(--t2c-primary);
    cursor: pointer;
}

.t2c-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.t2c-btn {
    padding: 0.625rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    line-height: 1.25;
    border-radius: var(--t2c-radius-sm);
    border: 1px solid transparent;
    cursor: pointer;
    transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
    -webkit-tap-highlight-color: transparent;
}

.t2c-btn-primary {
    background: var(--t2c-primary);
    color: #fff;
}

.t2c-btn-primary:hover {
    background: var(--t2c-primary-hover);
}

.t2c-btn-primary:focus-visible {
    outline: none;
    box-shadow: var(--t2c-shadow-focus);
}

.t2c-btn-secondary {
    background: var(--t2c-bg);
    color: var(--t2c-text);
    border-color: var(--t2c-border);
}

.t2c-btn-secondary:hover {
    background: var(--t2c-border);
}

.t2c-btn-outline {
    background: transparent;
    color: var(--t2c-text);
    border-color: var(--t2c-border);
}

.t2c-btn-outline:hover {
    background: var(--t2c-bg);
    border-color: var(--t2c-muted);
}

.t2c-btn:focus-visible {
    outline: none;
    box-shadow: var(--t2c-shadow-focus);
}

.t2c-status {
    min-height: 1.25rem;
    padding: 0.5rem 0;
    font-size: 0.8125rem;
    color: var(--t2c-muted);
}

.t2c-status.is-success {
    color: var(--t2c-success);
}

.t2c-status.is-error {
    color: var(--t2c-error);
}

/* Tablet and up: bar in one row, left | right panels */
@media (min-width: 768px) {
    .t2c-card-bar {
        flex-direction: row;
        flex-wrap: wrap;
        align-items: center;
        justify-content: space-between;
        padding: 1rem 1.25rem;
    }

    .t2c-options {
        gap: 1rem 1.5rem;
    }

    .t2c-actions {
        gap: 0.5rem;
    }

    .t2c-card-body {
        display: flex;
        flex-direction: row;
        gap: 0;
        padding: 0;
    }

    .t2c-panel {
        flex: 1;
        padding: 1.25rem;
        min-height: 400px;
    }

    .t2c-panel-left {
        border-right: 1px solid var(--t2c-border);
    }

    .t2c-panel .t2c-textarea {
        flex: 1;
        min-height: 0;
    }

    .t2c-status {
        margin-top: 0.75rem;
    }
}