:root {
    --brand-blue:       #004478;
    --brand-dark-blue:  #164374;
    --brand-yellow:     #ffcb05;
    --brand-yellow-hover: #ffc400;
    --brand-light-blue: #97d1e8;
    --brand-bg:         #ecf0f1;
    --brand-white:      #ffffff;
    --text-main:        #333333;
    --text-muted:       #666666;
    --border-color:     #dcdcdc;
}

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

body {
    font-family: 'Open Sans', sans-serif;
    background-color: var(--brand-bg);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

h1, h2, h3 {
    font-family: 'Montserrat', sans-serif;
}

/* ── Header ──────────────────────────────────────────────────────────────── */
.app-header {
    background: var(--brand-blue);
    color: var(--brand-white);
    padding: 0.6rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-shrink: 0;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.header-logo-img {
    height: 40px;
    width: auto;
    border-radius: 6px;
    background: var(--brand-white);
    padding: 3px;
}

.header-logo h1 {
    font-size: 1.2rem;
    margin: 0;
    color: var(--brand-white);
    white-space: nowrap;
}

.header-logo p {
    color: var(--brand-light-blue);
    margin: 0;
    font-size: 0.75rem;
}

/* ── Page wrapper ────────────────────────────────────────────────────────── */
.page-wrapper {
    max-width: 900px;
    width: 100%;
    margin: 2rem auto;
    padding: 0 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    flex: 1;
}

/* ── Card ────────────────────────────────────────────────────────────────── */
.card {
    background: var(--brand-white);
    border-radius: 12px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
    overflow: hidden;
}

.card-header {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--border-color);
    background: #f8fbfd;
}

.card-icon {
    font-size: 1.8rem;
    color: var(--brand-blue);
    flex-shrink: 0;
    margin-top: 0.1rem;
}

.card-header h2 {
    font-size: 1.2rem;
    color: var(--brand-blue);
    margin-bottom: 0.25rem;
}

.card-header p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.card-header code {
    background: #eef4f8;
    padding: 1px 5px;
    border-radius: 3px;
    font-size: 0.8rem;
    color: var(--brand-blue);
}

/* ── Upload area ─────────────────────────────────────────────────────────── */
.upload-area {
    border: 2px dashed var(--brand-light-blue);
    border-radius: 8px;
    padding: 2.5rem 2rem;
    margin: 1.5rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
    background: #fafcfe;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--brand-blue);
    background: #f0f7fb;
}

.upload-icon {
    font-size: 2.5rem;
    color: var(--brand-light-blue);
    margin-bottom: 0.75rem;
    display: block;
    transition: color 0.2s;
}

.upload-area:hover .upload-icon,
.upload-area.dragover .upload-icon {
    color: var(--brand-blue);
}

.upload-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: 0.25rem;
}

.upload-sub {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
}

/* ── Buttons ─────────────────────────────────────────────────────────────── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-family: 'Open Sans', sans-serif;
    font-weight: 600;
    padding: 0.6rem 1.5rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.9rem;
    text-decoration: none;
}

.btn-primary {
    background: var(--brand-blue);
    color: var(--brand-white);
}
.btn-primary:hover { background: var(--brand-dark-blue); }

.btn-accent {
    background: var(--brand-yellow);
    color: var(--brand-blue);
    font-size: 1rem;
    padding: 0.75rem 2rem;
    box-shadow: 0 4px 12px rgba(255, 203, 5, 0.35);
}
.btn-accent:hover {
    background: var(--brand-yellow-hover);
    transform: translateY(-1px);
}

.btn-outline-white {
    background: transparent;
    color: var(--brand-white);
    border: 1px solid rgba(255, 255, 255, 0.4);
    font-size: 0.82rem;
    padding: 0.4rem 0.9rem;
}
.btn-outline-white:hover { background: rgba(255, 255, 255, 0.12); }

/* ── Sheet picker ────────────────────────────────────────────────────────── */
.sheet-picker {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: #f0f7fb;
    border: 1px solid var(--brand-light-blue);
    border-radius: 6px;
    padding: 0.9rem 2rem;
    margin: 0 2rem 1.5rem;
    font-size: 0.9rem;
}

.sheet-picker i { color: var(--brand-blue); flex-shrink: 0; }

.sheet-picker select {
    padding: 0.4rem 0.75rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-family: 'Open Sans', sans-serif;
    font-size: 0.9rem;
    flex: 1;
    outline: none;
}
.sheet-picker select:focus { border-color: var(--brand-blue); }

/* ── Status ──────────────────────────────────────────────────────────────── */
.status-message {
    margin: 0 2rem 1.5rem;
    padding: 0.9rem 1.25rem;
    border-radius: 6px;
    font-size: 0.9rem;
}

.status-success { background: #e8f5e9; color: #2e7d32; border: 1px solid #c8e6c9; }
.status-error   { background: #fce4e4; color: #c62828; border: 1px solid #ffcdd2; }
.status-warning { background: #fff8e1; color: #e65100; border: 1px solid #ffe0b2; }
.status-info    { background: #e3f2fd; color: #0d47a1; border: 1px solid #bbdefb; }

/* ── Actions ─────────────────────────────────────────────────────────────── */
.actions-area {
    padding: 0 2rem 2rem;
    text-align: center;
}

.hidden { display: none; }

/* ── Preview section ─────────────────────────────────────────────────────── */
.preview-section {
    background: var(--brand-white);
    border-radius: 12px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
    overflow: hidden;
}

.preview-detection {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    background: #f0f7fb;
    border-bottom: 1px solid #d0e8f5;
    padding: 0.85rem 1.5rem;
    font-size: 0.875rem;
    color: var(--brand-dark-blue);
    line-height: 1.6;
}

.detection-note {
    font-size: 0.8rem;
    color: var(--text-muted, #666);
}

/* ── Column checklist ────────────────────────────────────────────────────── */
.column-checklist {
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid #eee;
}

.column-checklist h3 {
    font-size: 0.9rem;
    margin-bottom: 0.9rem;
    color: var(--text-main);
}

.checklist-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
    gap: 0.4rem;
}

.checklist-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.35rem 0.65rem;
    border-radius: 4px;
    font-size: 0.8rem;
}

.checklist-item.found            { background: #e8f5e9; color: #2e7d32; }
.checklist-item.missing-optional { background: #fff8e1; color: #795548; }
.checklist-item.missing-critical { background: #fce4e4; color: #c62828; font-weight: 600; }

.checklist-icon { font-weight: 700; flex-shrink: 0; }
.checklist-key  { flex: 1; font-family: monospace; font-size: 0.78rem; }

.checklist-badge {
    font-size: 0.65rem;
    background: #c62828;
    color: white;
    padding: 1px 5px;
    border-radius: 3px;
    text-transform: uppercase;
    flex-shrink: 0;
}

.extra-columns {
    margin-top: 0.75rem;
    font-size: 0.8rem;
    color: #555;
}

.extra-columns code {
    background: #f0f0f0;
    padding: 1px 5px;
    border-radius: 3px;
    font-size: 0.75rem;
}

/* ── Sample data table ───────────────────────────────────────────────────── */
.sample-data {
    padding: 1.25rem 1.5rem;
}

.sample-data h3 {
    font-size: 0.9rem;
    margin-bottom: 0.9rem;
    color: var(--text-main);
}

.sample-table-wrap {
    overflow-x: auto;
    border-radius: 6px;
    border: 1px solid #e0e0e0;
}

.sample-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.78rem;
    white-space: nowrap;
}

.sample-table th {
    background: #f7f9fa;
    padding: 0.45rem 0.75rem;
    text-align: left;
    border-bottom: 2px solid #e0e0e0;
    font-family: 'Montserrat', sans-serif;
    font-size: 0.72rem;
    color: var(--brand-dark-blue);
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.sample-table td {
    padding: 0.45rem 0.75rem;
    border-bottom: 1px solid #f0f0f0;
    max-width: 200px;
    overflow: hidden;
    text-overflow: ellipsis;
    color: var(--text-main);
}

.sample-table tbody tr:nth-child(even) { background: #fafafa; }
.sample-table tbody tr:hover           { background: #f0f7fb; }

/* ── Footer ──────────────────────────────────────────────────────────────── */
.app-footer {
    background: var(--brand-blue);
    color: var(--brand-light-blue);
    text-align: center;
    padding: 0.75rem 2rem;
    font-size: 0.82rem;
    flex-shrink: 0;
    margin-top: auto;
}

/* ── Tablet (no layout changes needed; max-width constrains nicely) ──────── */
@media (max-width: 768px) {
    .page-wrapper {
        margin: 1.5rem auto;
        padding: 0 1rem;
    }
}

/* ── Mobile ──────────────────────────────────────────────────────────────── */
@media (max-width: 640px) {

    /* Header: keep logo + back-btn on one line */
    .app-header {
        padding: 0 0.75rem;
        min-height: 52px;
        gap: 0.5rem;
    }

    .header-logo {
        flex: 1;
        min-width: 0;
        gap: 0.5rem;
    }

    .header-logo-img {
        height: 28px;
        flex-shrink: 0;
    }

    .header-logo h1 {
        font-size: 0.9rem;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }

    .header-logo p {
        display: none; /* hide subtitle on phone — not enough room */
    }

    /* Shrink back button to icon + short label */
    .btn-outline-white {
        font-size: 0.75rem;
        padding: 0.4rem 0.6rem;
        flex-shrink: 0;
        white-space: nowrap;
    }

    /* Page wrapper */
    .page-wrapper {
        margin: 0.75rem auto;
        padding: 0 0.75rem;
        gap: 0.75rem;
    }

    /* Card header: shrink icon, tighten padding */
    .card-header {
        padding: 0.85rem 1rem;
        gap: 0.65rem;
        align-items: center;
    }

    .card-icon {
        font-size: 1.4rem;
    }

    .card-header h2 {
        font-size: 1rem;
        margin-bottom: 0.15rem;
    }

    .card-header p {
        font-size: 0.8rem;
        line-height: 1.5;
    }

    /* Upload area */
    .upload-area {
        margin: 0.75rem;
        padding: 1.5rem 1rem;
    }

    .upload-icon {
        font-size: 2rem;
        margin-bottom: 0.5rem;
    }

    .upload-title {
        font-size: 0.95rem;
    }

    .upload-sub {
        font-size: 0.8rem;
        margin-bottom: 1rem;
    }

    /* Sheet picker: stack vertically */
    .sheet-picker {
        flex-wrap: wrap;
        padding: 0.75rem 0.75rem;
        margin: 0 0.75rem 0.75rem;
        gap: 0.5rem;
        font-size: 0.85rem;
    }

    .sheet-picker label {
        flex: 1 1 100%;
    }

    .sheet-picker select {
        flex: 1 1 100%;
    }

    /* Status */
    .status-message {
        margin: 0 0.75rem 0.75rem;
        font-size: 0.85rem;
        word-break: break-word;
    }

    /* Actions */
    .actions-area {
        padding: 0 0.75rem 1.25rem;
    }

    .btn-accent {
        width: 100%;
        justify-content: center;
        font-size: 0.95rem;
        padding: 0.85rem 1.25rem;
    }

    /* General touch targets */
    .btn {
        min-height: 44px;
    }

    /* Preview: detection bar wraps on small screens */
    .preview-detection {
        padding: 0.7rem 0.75rem;
        font-size: 0.8rem;
        flex-wrap: wrap;
        align-items: flex-start;
        line-height: 1.6;
    }

    /* Column checklist */
    .column-checklist {
        padding: 0.85rem 0.75rem;
    }

    .checklist-grid {
        grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
        gap: 0.3rem;
    }

    .checklist-item {
        font-size: 0.75rem;
        padding: 0.3rem 0.5rem;
    }

    .checklist-key {
        font-size: 0.72rem;
    }

    /* Sample data */
    .sample-data {
        padding: 0.85rem 0.75rem;
    }

    .sample-data h3 {
        font-size: 0.82rem;
        margin-bottom: 0.6rem;
    }

    /* Hint that the table scrolls horizontally */
    .sample-table-wrap::before {
        content: 'Scroll horizontally to see all columns →';
        display: block;
        font-size: 0.7rem;
        color: var(--text-muted);
        margin-bottom: 0.4rem;
        font-style: italic;
    }

    .extra-columns {
        font-size: 0.75rem;
        line-height: 1.6;
    }

    /* Footer */
    .app-footer {
        font-size: 0.75rem;
        padding: 0.6rem 1rem;
    }
}