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

:root {
    --bg: #1e1e1e;
    --grid-bg: #1e1e1e;
    --surface: #252526;
    --header-bg: #2d2d30;
    --header-bg-hover: #3a3a3d;
    --border: #3c3c3c;
    --border-strong: #505050;
    --text: #d4d4d4;
    --text-dim: #808080;
    --text-bright: #ffffff;
    --accent: #4fc1ff;
    --accent-dim: rgba(79, 193, 255, 0.12);
    --select: rgba(38, 79, 120, 0.6);
    --select-border: #007acc;
    --tab-active: #1e1e1e;
    --tab-inactive: #2d2d30;
    --green: #6a9955;
    --yellow: #dcdcaa;
    --blue: #569cd6;
    --orange: #ce9178;
    --highlight: rgba(255, 255, 0, 0.15);
    --row-num-w: 50px;
    --col-header-h: 24px;
    --formula-h: 32px;
    --tab-bar-h: 28px;
    --cell-h: 24px;
    --cell-min-w: 100px;
}

html, body {
    height: 100%;
    overflow: hidden;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 12px;
    background: var(--bg);
    color: var(--text);
}

/* ===== Formula Bar ===== */
.formula-bar {
    height: var(--formula-h);
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 1px;
    gap: 0;
    z-index: 200;
    position: relative;
}

.formula-bar-left {
    display: flex;
    align-items: center;
    flex: 1;
    min-width: 0;
    height: 100%;
}

.cell-ref {
    width: var(--row-num-w);
    min-width: var(--row-num-w);
    text-align: center;
    font-weight: 600;
    color: var(--text);
    font-size: 11px;
    border-right: 1px solid var(--border);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--header-bg);
}

.fx-label {
    padding: 0 8px;
    color: var(--text-dim);
    font-style: italic;
    font-size: 11px;
    border-right: 1px solid var(--border);
    height: 100%;
    display: flex;
    align-items: center;
    user-select: none;
}

.formula-display {
    flex: 1;
    padding: 0 8px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    font-size: 11px;
    color: var(--text);
    height: 100%;
    display: flex;
    align-items: center;
}

.formula-bar-right {
    display: flex;
    align-items: center;
    gap: 4px;
    padding-right: 6px;
}

.search-box {
    display: flex;
    align-items: center;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 3px;
    padding: 0 6px;
    height: 22px;
}

.search-box:focus-within {
    border-color: var(--select-border);
}

.search-box svg {
    color: var(--text-dim);
    flex-shrink: 0;
}

.search-box input {
    background: none;
    border: none;
    outline: none;
    color: var(--text);
    font-size: 11px;
    padding: 0 6px;
    width: 160px;
    font-family: inherit;
}

.search-box input::placeholder { color: var(--text-dim); }

.search-count {
    font-size: 10px;
    color: var(--accent);
    font-weight: 600;
    min-width: 30px;
    text-align: right;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: 4px;
    background: var(--header-bg);
    color: var(--green);
    border: 1px solid var(--border);
    border-radius: 3px;
    padding: 0 8px;
    height: 22px;
    font-size: 11px;
    font-weight: 600;
    text-decoration: none;
    transition: background 0.15s;
    white-space: nowrap;
}

.download-btn:hover {
    background: var(--header-bg-hover);
}

/* ===== Grid Layout ===== */
.grid-wrapper {
    display: grid;
    grid-template-columns: var(--row-num-w) 1fr;
    grid-template-rows: var(--col-header-h) 1fr;
    flex: 1;
    overflow: hidden;
    position: relative;
    /* Fill remaining space between formula bar and tab bar */
    height: calc(100vh - var(--formula-h) - var(--tab-bar-h));
}

/* Corner cell (top-left) */
.corner-cell {
    grid-row: 1;
    grid-column: 1;
    background: var(--header-bg);
    border-right: 1px solid var(--border-strong);
    border-bottom: 1px solid var(--border-strong);
    z-index: 30;
}

/* Column headers (A, B, C...) */
.col-header-track {
    grid-row: 1;
    grid-column: 2;
    overflow: hidden;
    background: var(--header-bg);
    border-bottom: 1px solid var(--border-strong);
    z-index: 20;
}

.col-headers {
    display: flex;
    height: 100%;
}

.col-header {
    min-width: var(--cell-min-w);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 600;
    color: var(--text-dim);
    border-right: 1px solid var(--border);
    user-select: none;
    cursor: default;
    flex-shrink: 0;
}

.col-header:hover {
    background: var(--header-bg-hover);
    color: var(--text);
}

/* Row number headers (1, 2, 3...) */
.row-header-track {
    grid-row: 2;
    grid-column: 1;
    overflow: hidden;
    background: var(--header-bg);
    border-right: 1px solid var(--border-strong);
    z-index: 20;
}

.row-headers {
    width: 100%;
}

.row-header {
    height: var(--cell-h);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    color: var(--text-dim);
    border-bottom: 1px solid var(--border);
    user-select: none;
    cursor: default;
}

.row-header:hover {
    background: var(--header-bg-hover);
    color: var(--text);
}

/* Grid viewport (scrollable area) */
.grid-viewport {
    grid-row: 2;
    grid-column: 2;
    overflow: auto;
    background: var(--grid-bg);
    position: relative;
}

.loading {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    color: var(--text-dim);
}

.spinner {
    width: 28px;
    height: 28px;
    border: 2px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
    margin-bottom: 10px;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* Table Cells */
table {
    border-collapse: collapse;
    table-layout: fixed;
}

table td {
    height: var(--cell-h);
    min-width: var(--cell-min-w);
    max-width: 300px;
    padding: 0 6px;
    border-right: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    font-size: 11px;
    color: var(--text);
    cursor: cell;
    vertical-align: middle;
    line-height: var(--cell-h);
}

table td:hover {
    outline: 1px solid var(--select-border);
    outline-offset: -1px;
}

table td.selected {
    outline: 2px solid var(--select-border);
    outline-offset: -1px;
    background: var(--select);
}

table td.num {
    text-align: right;
    font-variant-numeric: tabular-nums;
    color: var(--blue);
}

table td.pct {
    text-align: right;
    color: var(--green);
}

table td.pct.negative {
    color: #f14c4c;
}

table td.header-cell {
    background: var(--header-bg);
    font-weight: 600;
    color: var(--text-bright);
    font-size: 11px;
}

table td.title-cell {
    font-weight: 700;
    font-size: 13px;
    color: var(--accent);
    background: var(--surface);
    padding: 0 10px;
}

table td.subtitle-cell {
    font-size: 11px;
    color: var(--text-dim);
    background: var(--surface);
    padding: 0 10px;
}

table td.empty-cell {
    background: var(--surface);
}

table td.highlight {
    background: var(--highlight);
}

/* ===== Bottom Sheet Tabs ===== */
.sheet-tabs-bar {
    height: var(--tab-bar-h);
    background: var(--surface);
    border-top: 1px solid var(--border);
    display: flex;
    align-items: stretch;
    z-index: 200;
    position: relative;
}

.sheet-tabs-nav {
    display: flex;
    align-items: center;
    padding: 0 2px;
    gap: 1px;
    border-right: 1px solid var(--border);
}

.nav-arrow {
    background: none;
    border: none;
    color: var(--text-dim);
    font-size: 9px;
    cursor: pointer;
    padding: 2px 6px;
    border-radius: 2px;
    height: 20px;
    display: flex;
    align-items: center;
}

.nav-arrow:hover {
    background: var(--header-bg-hover);
    color: var(--text);
}

.sheet-tabs-scroll {
    flex: 1;
    overflow-x: auto;
    overflow-y: hidden;
    scrollbar-width: none;
}

.sheet-tabs-scroll::-webkit-scrollbar { display: none; }

.sheet-tabs {
    display: flex;
    height: 100%;
    align-items: flex-end;
}

.sheet-tab {
    background: var(--tab-inactive);
    border: 1px solid var(--border);
    border-bottom: none;
    border-radius: 4px 4px 0 0;
    color: var(--text-dim);
    font-family: inherit;
    font-size: 11px;
    font-weight: 500;
    padding: 4px 14px;
    cursor: pointer;
    white-space: nowrap;
    transition: all 0.15s;
    margin-left: -1px;
    position: relative;
    height: 24px;
    display: flex;
    align-items: center;
}

.sheet-tab:first-child {
    margin-left: 4px;
}

.sheet-tab:hover {
    background: var(--header-bg-hover);
    color: var(--text);
}

.sheet-tab.active {
    background: var(--tab-active);
    color: var(--text-bright);
    font-weight: 600;
    border-bottom: 1px solid var(--tab-active);
    z-index: 1;
    height: 26px;
}

.status-bar {
    display: flex;
    align-items: center;
    padding: 0 12px;
    margin-left: auto;
    border-left: 1px solid var(--border);
}

.status-text {
    font-size: 11px;
    color: var(--text-dim);
}

/* Scrollbar */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--surface); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 5px; border: 2px solid var(--surface); }
::-webkit-scrollbar-thumb:hover { background: var(--border-strong); }
::-webkit-scrollbar-corner { background: var(--surface); }

/* Responsive  */
@media (max-width: 768px) {
    .search-box input { width: 100px; }
    .download-btn span { display: none; }
    :root { --cell-min-w: 80px; --row-num-w: 40px; }
}