/* --- Design System & CSS Variables --- */
:root {
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    
    /* Light Mode Palette */
    --bg-app: #f4f6f9;
    --bg-card: rgba(255, 255, 255, 0.8);
    --border-card: rgba(226, 232, 240, 0.8);
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --primary-light: rgba(79, 70, 229, 0.1);
    
    --accent: #10b981;
    --accent-light: rgba(16, 185, 129, 0.1);
    
    --danger: #ef4444;
    --danger-light: rgba(239, 68, 68, 0.1);
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    
    --glass-blur: blur(12px);
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.dark-mode {
    /* Dark Mode Palette */
    --bg-app: #090d16;
    --bg-card: rgba(17, 24, 39, 0.7);
    --border-card: rgba(31, 41, 55, 0.7);
    
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: rgba(99, 102, 241, 0.15);
    
    --accent: #34d399;
    --accent-light: rgba(52, 211, 153, 0.15);
    
    --danger: #f87171;
    --danger-light: rgba(248, 113, 113, 0.15);
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -4px rgba(0, 0, 0, 0.5);
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-app);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition-normal), color var(--transition-normal);
    line-height: 1.5;
}

/* --- Header --- */
.app-header {
    background-color: var(--bg-card);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border-bottom: 1px solid var(--border-card);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.header-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.logo-icon {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    width: 2.75rem;
    height: 2.75rem;
    border-radius: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
}

.logo-icon i {
    width: 1.5rem;
    height: 1.5rem;
}

.logo-text h1 {
    font-size: 1.25rem;
    font-weight: 800;
    letter-spacing: -0.025em;
    background: linear-gradient(to right, var(--text-primary), var(--primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.logo-subtext {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

.btn-icon {
    background: transparent;
    border: 1px solid var(--border-card);
    color: var(--text-secondary);
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

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

.light-mode .light-icon {
    display: none;
}

.dark-mode .dark-icon {
    display: none;
}

/* --- Main Layout --- */
.app-container {
    max-width: 1280px;
    width: 100%;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.grid-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

@media (min-width: 1024px) {
    .grid-layout {
        grid-template-columns: 1fr 1fr;
    }
}

/* --- Panel & Glass Card --- */
.panel {
    display: flex;
    flex-direction: column;
}

.glass-card {
    background-color: var(--bg-card);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--border-card);
    border-radius: 1.25rem;
    padding: 1.75rem;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-normal);
}

.panel-header {
    border-bottom: 1px solid var(--border-card);
    padding-bottom: 1.25rem;
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.panel-title {
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-primary);
}

.panel-title i {
    color: var(--primary);
}

.panel-subtitle {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* --- Tabs --- */
.tab-container {
    display: flex;
    background-color: var(--bg-app);
    border-radius: 0.75rem;
    padding: 0.35rem;
    gap: 0.25rem;
    margin-bottom: 1.5rem;
}

.tab-btn {
    flex: 1;
    border: none;
    background: transparent;
    padding: 0.75rem 1rem;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    border-radius: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: all var(--transition-fast);
}

.tab-btn i {
    width: 1rem;
    height: 1rem;
}

.tab-btn.active {
    background-color: var(--bg-card);
    color: var(--primary);
    box-shadow: var(--shadow-sm);
}

/* --- Form Fields --- */
.input-group {
    margin-bottom: 1.25rem;
}

.input-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-wrapper input {
    width: 100%;
    padding: 0.75rem 2.5rem 0.75rem 1rem;
    font-size: 1.05rem;
    font-weight: 600;
    border: 1.5px solid var(--border-card);
    background-color: var(--bg-app);
    color: var(--text-primary);
    border-radius: 0.75rem;
    outline: none;
    transition: all var(--transition-fast);
}

.input-wrapper input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px var(--primary-light);
    background-color: var(--bg-card);
}

.input-suffix {
    position: absolute;
    right: 1rem;
    font-weight: 700;
    color: var(--text-muted);
}

.select-wrapper {
    position: relative;
}

.select-wrapper select {
    width: 100%;
    padding: 0.75rem 2.5rem 0.75rem 1rem;
    font-size: 0.95rem;
    font-weight: 500;
    border: 1.5px solid var(--border-card);
    background-color: var(--bg-app);
    color: var(--text-primary);
    border-radius: 0.75rem;
    outline: none;
    appearance: none;
    -webkit-appearance: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.select-wrapper select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px var(--primary-light);
}

.select-arrow {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    pointer-events: none;
    color: var(--text-secondary);
}

.input-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.35rem;
}

/* Counter */
.counter-wrapper {
    display: flex;
    align-items: center;
    border: 1.5px solid var(--border-card);
    border-radius: 0.75rem;
    background-color: var(--bg-app);
    overflow: hidden;
    max-width: 12rem;
}

.btn-counter {
    background: transparent;
    border: none;
    color: var(--text-primary);
    width: 3rem;
    height: 2.75rem;
    font-size: 1.25rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.btn-counter:hover {
    background-color: var(--border-card);
}

.counter-wrapper input {
    flex: 1;
    border: none;
    background: transparent;
    text-align: center;
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
    outline: none;
}

/* Radio Group */
.radio-group {
    display: flex;
    gap: 1.5rem;
    margin-top: 0.25rem;
}

.radio-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500 !important;
    cursor: pointer;
}

.radio-label input {
    display: none;
}

.radio-custom {
    width: 1.15rem;
    height: 1.15rem;
    border: 2px solid var(--text-muted);
    border-radius: 50%;
    display: inline-block;
    position: relative;
    transition: all var(--transition-fast);
}

.radio-label input:checked + .radio-custom {
    border-color: var(--primary);
}

.radio-label input:checked + .radio-custom::after {
    content: '';
    width: 0.55rem;
    height: 0.55rem;
    background-color: var(--primary);
    border-radius: 50%;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.hidden {
    display: none !important;
}

/* Advanced Settings */
.advanced-settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    cursor: pointer;
    border-top: 1px dashed var(--border-card);
    border-bottom: 1px dashed var(--border-card);
    margin: 1.5rem 0;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.9rem;
    transition: color var(--transition-fast);
}

.advanced-settings-header:hover {
    color: var(--primary);
}

.advanced-settings-header i {
    transition: transform var(--transition-fast);
}

.advanced-settings-header.active i#advanced-chevron {
    transform: rotate(90deg);
}

.advanced-settings-body {
    padding: 0.5rem 0 1.25rem 0;
}

.advanced-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.group-title {
    display: block;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.75rem;
}

.mini-input {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.mini-input label {
    margin: 0;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.mini-input input {
    width: 4.5rem;
    padding: 0.35rem 0.5rem;
    font-size: 0.85rem;
    font-weight: 600;
    border: 1.5px solid var(--border-card);
    border-radius: 0.5rem;
    background-color: var(--bg-app);
    color: var(--text-primary);
    text-align: right;
    outline: none;
}

.mini-input input:focus {
    border-color: var(--primary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: 0.75rem;
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-primary {
    background-color: var(--primary);
    color: white;
    box-shadow: 0 4px 10px rgba(79, 70, 229, 0.3);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-block {
    width: 100%;
}

.btn-outline {
    background: transparent;
    border: 1.5px solid var(--border-card);
    color: var(--text-secondary);
}

.btn-outline:hover:not(:disabled) {
    border-color: var(--primary);
    color: var(--primary);
    background-color: var(--primary-light);
}

.btn-outline:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* --- Results Panel --- */
.result-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-muted);
}

.placeholder-icon {
    width: 4rem;
    height: 4rem;
    border-radius: 50%;
    background-color: var(--bg-app);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--primary);
}

/* Highlight Cards */
.highlight-cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1.75rem;
}

.highlight-card {
    padding: 1.25rem;
    border-radius: 0.85rem;
    display: flex;
    flex-direction: column;
}

.main-highlight {
    background: linear-gradient(135deg, var(--primary), #3b82f6);
    color: white;
}

.main-highlight .card-label {
    color: rgba(255, 255, 255, 0.85);
}

.border-highlight {
    border: 1.5px solid var(--border-card);
    background-color: var(--bg-app);
}

.card-label {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.card-value {
    font-size: 1.35rem;
    font-weight: 800;
    margin-top: 0.35rem;
    word-break: break-all;
}

/* Visualization */
.visualization-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
    padding: 1rem;
    border: 1px solid var(--border-card);
    background-color: var(--bg-app);
    border-radius: 1rem;
}

@media (min-width: 640px) {
    .visualization-area {
        flex-direction: row;
    }
}

.chart-container {
    width: 10.5rem;
    height: 10.5rem;
    position: relative;
}

.chart-legend {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    width: 100%;
}

.legend-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.85rem;
    padding: 0.35rem 0;
    border-bottom: 1px solid var(--border-card);
}

.legend-label-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.legend-color {
    width: 0.75rem;
    height: 0.75rem;
    border-radius: 0.25rem;
}

.legend-label {
    font-weight: 600;
    color: var(--text-primary);
}

.legend-percentage {
    color: var(--text-muted);
    font-weight: 500;
}

.legend-value {
    font-weight: 700;
    color: var(--text-primary);
}

/* Exportable & Printable Sheet */
.exportable-sheet {
    display: flex;
    flex-direction: column;
    gap: 1.75rem;
}

.export-header-info {
    display: none; /* Only visible in exports */
}

.sheet-section {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.section-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 0.35rem;
    border-bottom: 1px dashed var(--border-card);
    padding-bottom: 0.35rem;
}

.section-title i {
    width: 1.15rem;
    height: 1.15rem;
    color: var(--primary);
}

/* Tables */
.detail-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.detail-table th, 
.detail-table td {
    padding: 0.65rem 0.5rem;
    border-bottom: 1px solid var(--border-card);
    text-align: left;
}

.detail-table th {
    font-weight: 700;
    color: var(--text-muted);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding-top: 0;
}

.detail-table td.text-right, 
.detail-table th.text-right {
    text-align: right;
}

.detail-table td.text-bold {
    font-weight: 700;
}

.detail-table tr.sub-row td {
    color: var(--text-secondary);
    padding-left: 1.25rem;
    font-size: 0.85rem;
}

.detail-table tr.total-row td {
    font-weight: 600;
    background-color: var(--primary-light);
    color: var(--primary);
}

.detail-table tr.grand-total-row td {
    font-size: 1rem;
    border-bottom: 2px double var(--primary);
    background-color: var(--primary-light);
}

.text-accent {
    color: var(--accent) !important;
}

.tax-highlight td {
    background-color: var(--danger-light);
    color: var(--danger) !important;
    font-weight: 600;
}

/* PIT Bracket list */
.pit-steps-container {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-top: 0.35rem;
}

.pit-step-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--bg-app);
    padding: 0.65rem 1rem;
    border-radius: 0.65rem;
    font-size: 0.8rem;
    border: 1px solid var(--border-card);
}

.pit-step-item.active {
    border-color: var(--danger);
    background-color: var(--danger-light);
}

.pit-step-title {
    font-weight: 600;
}

.pit-step-rate {
    font-weight: 700;
    color: var(--danger);
}

.pit-step-amount {
    font-weight: 700;
}

/* --- History Section --- */
.panel-history {
    margin-top: 1rem;
}

.panel-header-history {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.panel-header-history h3 {
    font-size: 1rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.panel-header-history h3 i {
    width: 1.15rem;
    height: 1.15rem;
    color: var(--primary);
}

.btn-clear-history {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: color var(--transition-fast);
}

.btn-clear-history:hover {
    color: var(--danger);
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
    max-height: 15rem;
    overflow-y: auto;
    padding-right: 0.25rem;
}

.history-empty {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.history-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-card);
    background-color: var(--bg-app);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.history-item:hover {
    border-color: var(--primary);
    transform: translateX(2px);
    background-color: var(--bg-card);
}

.history-item-left {
    display: flex;
    flex-direction: column;
    gap: 0.15rem;
}

.history-item-title {
    font-weight: 700;
    font-size: 0.85rem;
}

.history-item-subtitle {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.history-item-right {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 800;
    font-size: 0.95rem;
    color: var(--primary);
}

.history-item-arrow {
    color: var(--text-muted);
}

/* --- Footer --- */
.app-footer {
    text-align: center;
    padding: 2rem 1.5rem;
    color: var(--text-muted);
    font-size: 0.8rem;
    border-top: 1px solid var(--border-card);
    background-color: var(--bg-card);
    margin-top: 2rem;
}

.footer-container {
    max-width: 1280px;
    margin: 0 auto;
}

/* --- PDF Export Styles Override --- */
@media print {
    body {
        background-color: #fff !important;
        color: #000 !important;
    }
    .exportable-sheet {
        padding: 2rem !important;
    }
    .detail-table tr.total-row td,
    .detail-table tr.grand-total-row td,
    .tax-highlight td {
        background-color: #f1f5f9 !important;
        color: #000 !important;
        border-bottom: 1px solid #cbd5e1 !important;
    }
}