/* ===== CSS Custom Properties (Vercel Design Tokens) ===== */
:root {
    --color-bg: #ffffff;
    --color-text: #171717;
    --color-text-secondary: #4d4d4d;
    --color-text-muted: #666666;
    --color-border: rgba(0, 0, 0, 0.08);
    --color-border-light: #ebebeb;
    --color-surface-tint: #fafafa;
    --color-error-bg: #fef2f2;
    --color-error-text: #b91c1c;
    --color-error-border: #fecaca;
    --color-primary: #171717;
    --color-primary-hover: #000000;
    --color-ghost-bg: #ffffff;
    --color-ghost-hover: #f5f5f5;
    --color-focus: hsla(212, 100%, 48%, 1);
    
    --font-sans: 'Geist', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'Geist Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, 'Liberation Mono', 'Courier New', monospace;
    
    --shadow-border: 0px 0px 0px 1px var(--color-border);
    --shadow-card: 0px 0px 0px 1px var(--color-border), 0px 2px 2px rgba(0,0,0,0.04), 0px 8px 8px -8px rgba(0,0,0,0.04), 0px 0px 0px 1px var(--color-surface-tint);
    --shadow-card-hover: 0px 0px 0px 1px var(--color-border), 0px 4px 4px rgba(0,0,0,0.06), 0px 12px 12px -8px rgba(0,0,0,0.06), 0px 0px 0px 1px var(--color-surface-tint);
    
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-pill: 9999px;
    
    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 24px;
    --space-6: 32px;
    --space-8: 48px;
    --space-10: 64px;
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; }
html { font-size: 16px; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
body {
    margin: 0;
    font-family: var(--font-sans);
    font-size: 16px;
    font-weight: 400;
    line-height: 1.56;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
}

/* ===== Layout ===== */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--space-6) var(--space-4) var(--space-10);
}

@media (min-width: 768px) {
    .container { padding: var(--space-10) var(--space-6) var(--space-10); }
}

/* ===== Header ===== */
.header {
    text-align: center;
    margin-bottom: var(--space-8);
}

.heading {
    font-family: var(--font-sans);
    font-size: 32px;
    font-weight: 600;
    line-height: 1.25;
    letter-spacing: -1.28px;
    color: var(--color-text);
    margin: 0 0 var(--space-3);
}

.subtext {
    font-size: 18px;
    font-weight: 400;
    line-height: 1.56;
    color: var(--color-text-secondary);
    margin: 0;
    max-width: 560px;
    margin-left: auto;
    margin-right: auto;
}

/* ===== Toolbar ===== */
.toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-3);
    margin-bottom: var(--space-4);
    flex-wrap: wrap;
}

.btn {
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 500;
    line-height: 1.43;
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    transition: background-color 0.15s ease, box-shadow 0.15s ease;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.btn:focus-visible {
    outline: 2px solid var(--color-focus);
    outline-offset: 2px;
}

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

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

.btn-ghost {
    background: var(--color-ghost-bg);
    color: var(--color-text);
    box-shadow: var(--shadow-border);
}

.btn-ghost:hover {
    background: var(--color-ghost-hover);
}

/* ===== Alert ===== */
.alert {
    background: var(--color-error-bg);
    color: var(--color-error-text);
    border: 1px solid var(--color-error-border);
    border-radius: var(--radius-md);
    padding: var(--space-4) var(--space-4);
    font-size: 14px;
    line-height: 1.5;
    margin-bottom: var(--space-4);
}

.alert strong { font-weight: 600; display: block; margin-bottom: var(--space-2); }
.alert ul { margin: 0; padding-left: 20px; }
.alert li { margin-bottom: 4px; }

.hidden { display: none !important; }

/* ===== Card ===== */
.card {
    background: var(--color-bg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-card);
    padding: var(--space-5);
    transition: box-shadow 0.2s ease;
}

.card:hover { box-shadow: var(--shadow-card-hover); }

/* ===== Spreadsheet Container ===== */
#spreadsheet-container {
    min-height: 420px;
    overflow-x: auto;
    border-radius: 4px;
}

/* Override Jspreadsheet styles untuk konsistensi */
#spreadsheet-container .jexcel {
    font-family: var(--font-sans) !important;
    font-size: 14px !important;
}

#spreadsheet-container .jexcel thead th {
    background: var(--color-surface-tint) !important;
    color: var(--color-text) !important;
    font-weight: 500 !important;
    font-size: 13px !important;
    letter-spacing: -0.32px !important;
    border-bottom: 1px solid var(--color-border-light) !important;
    padding: 10px 12px !important;
}

#spreadsheet-container .jexcel tbody td {
    border-right: 1px solid var(--color-border-light) !important;
    border-bottom: 1px solid var(--color-border-light) !important;
    padding: 8px 12px !important;
    vertical-align: middle !important;
}

#spreadsheet-container .jexcel tbody td:last-child {
    border-right: none !important;
}

#spreadsheet-container .jexcel tbody tr:last-child td {
    border-bottom: none !important;
}

/* Highlight error cell (applied via JS) */
#spreadsheet-container .jexcel tbody td.error-highlight {
    background-color: #fef2f2 !important;
    border-color: #fecaca !important;
}

/* Focus state untuk cell editing */
#spreadsheet-container .jexcel tbody td.editor input,
#spreadsheet-container .jexcel tbody td.editor textarea {
    font-family: var(--font-sans) !important;
    font-size: 14px !important;
    border: 1px solid var(--color-focus) !important;
    box-shadow: 0 0 0 2px rgba(147, 197, 253, 0.3) !important;
    outline: none !important;
}

/* ===== Hint ===== */
.hint {
    font-size: 13px;
    font-weight: 400;
    color: var(--color-text-muted);
    margin: var(--space-4) 0 0;
    text-align: center;
}

/* ===== Footer ===== */
.footer {
    margin-top: var(--space-10);
    padding-top: var(--space-6);
    border-top: 1px solid var(--color-border-light);
    text-align: center;
}

.footer p {
    font-size: 13px;
    color: var(--color-text-muted);
    margin: 0;
}

.footer a {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.15s;
}

.footer a:hover { color: var(--color-text); text-decoration: underline; }