/* Design System Variables & Tokens */
:root {
    --bg-main: linear-gradient(135deg, #f8fafc 0%, #eff6ff 100%);
    --bg-glow-1: rgba(99, 102, 241, 0.15);
    --bg-glow-2: rgba(6, 182, 212, 0.12);
    --card-bg: rgba(255, 255, 255, 0.55);
    --card-border: rgba(255, 255, 255, 0.6);
    --card-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.04), 
                   0 4px 6px -1px rgba(0, 0, 0, 0.02);
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --primary-glow: rgba(99, 102, 241, 0.25);
    --secondary: #64748b;
    --secondary-hover: #475569;
    --accent: #06b6d4;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    
    --font-family: 'Inter', 'Noto Sans KR', sans-serif;
    --border-radius-lg: 20px;
    --border-radius-md: 12px;
    --border-radius-sm: 8px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode Overrides */
.theme-dark {
    --bg-main: linear-gradient(135deg, #090d16 0%, #05070c 100%);
    --bg-glow-1: rgba(99, 102, 241, 0.08);
    --bg-glow-2: rgba(6, 182, 212, 0.06);
    --card-bg: rgba(15, 23, 42, 0.5);
    --card-border: rgba(255, 255, 255, 0.08);
    --card-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.2),
                   0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-glow: rgba(99, 102, 241, 0.4);
    --secondary: #475569;
    --secondary-hover: #334155;
    --accent: #22d3ee;
}

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

body {
    font-family: var(--font-family);
    background: var(--bg-main);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    position: relative;
    overflow-x: hidden;
    transition: var(--transition);
}

/* Decorative Glow Backgrounds */
.bg-glow {
    position: absolute;
    width: 600px;
    height: 600px;
    border-radius: 50%;
    filter: blur(120px);
    z-index: -1;
    pointer-events: none;
    transition: var(--transition);
}
.bg-glow-1 {
    top: -100px;
    left: -100px;
    background: var(--bg-glow-1);
}
.bg-glow-2 {
    bottom: -100px;
    right: -100px;
    background: var(--bg-glow-2);
}

/* Layout App Container */
.app-container {
    width: 100%;
    max-width: 680px;
    padding: 24px 16px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Header Styling */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 8px;
}
.brand {
    display: flex;
    align-items: center;
    gap: 14px;
}
.brand-icon {
    width: 36px;
    height: 36px;
    color: var(--primary);
}
.brand-text h1 {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}
.brand-text span {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Buttons System */
.icon-btn {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    padding: 10px;
    border-radius: 50%;
    cursor: pointer;
    box-shadow: var(--card-shadow);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}
.icon-btn:hover {
    transform: translateY(-2px);
    border-color: var(--primary);
    box-shadow: 0 4px 12px var(--primary-glow);
}
.icon-btn:active {
    transform: translateY(0);
}
.sun-icon { display: block; width: 20px; height: 20px; }
.moon-icon { display: none; width: 20px; height: 20px; }

.theme-dark .sun-icon { display: none; }
.theme-dark .moon-icon { display: block; }

/* Navigation Tab Bar */
.app-nav {
    display: flex;
    gap: 12px;
    border-bottom: 1px solid var(--card-border);
    padding-bottom: 4px;
}
.nav-tab {
    background: none;
    border: none;
    padding: 12px 20px;
    font-family: var(--font-family);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    border-radius: var(--border-radius-sm);
    transition: var(--transition);
}
.nav-tab svg {
    width: 18px;
    height: 18px;
}
.nav-tab:hover {
    color: var(--primary);
    background: rgba(99, 102, 241, 0.05);
}
.nav-tab.active {
    color: var(--primary);
    background: rgba(99, 102, 241, 0.08);
    box-shadow: inset 0 -2px 0 var(--primary);
}

/* Tab panes styling */
.tab-pane {
    display: none;
    animation: fadeIn 0.4s ease;
}
.tab-pane.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Layout Grid system */
.layout-grid {
    display: flex;
    flex-direction: column;
    gap: 24px;
    max-width: 580px;
    margin: 0 auto;
}

/* Card Styling (Glassmorphism) */
.card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--card-shadow);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    transition: var(--transition);
}
.card:hover {
    box-shadow: 0 12px 40px 0 rgba(31, 38, 135, 0.06), var(--card-shadow);
}
.card.highlight-border {
    border-color: rgba(99, 102, 241, 0.25);
    background: linear-gradient(180deg, var(--card-bg) 0%, rgba(99, 102, 241, 0.02) 100%);
}

.card-header {
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.card-header h2 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}
.card-header h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
}
.subtitle {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Form Styles */
.form-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
}
.input-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.input-group label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 4px;
}
.tooltip-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--text-muted);
    color: #fff;
    font-size: 0.65rem;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    cursor: help;
    font-weight: bold;
}

input[type="date"],
input[type="text"],
input[type="number"],
select {
    width: 100%;
    padding: 12px 16px;
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid var(--card-border);
    border-radius: var(--border-radius-md);
    font-family: var(--font-family);
    font-size: 0.95rem;
    color: var(--text-primary);
    transition: var(--transition);
    outline: none;
}
.theme-dark input[type="date"],
.theme-dark input[type="text"],
.theme-dark input[type="number"],
.theme-dark select {
    background: rgba(0, 0, 0, 0.2);
}

input:focus, select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px var(--primary-glow);
    background: rgba(255, 255, 255, 0.5);
}
.theme-dark input:focus, .theme-dark select:focus {
    background: rgba(0, 0, 0, 0.3);
}

/* Alert Boxes & Badges */
.alert-info {
    background: rgba(99, 102, 241, 0.08);
    border-left: 4px solid var(--primary);
    padding: 12px 16px;
    border-radius: var(--border-radius-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
}
.alert-text {
    color: var(--text-secondary);
}
.alert-text strong {
    color: var(--primary);
}
.badge {
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
}
.badge-warning {
    background: rgba(245, 158, 11, 0.15);
    color: var(--warning);
}
.badge-success {
    background: rgba(16, 185, 129, 0.15);
    color: var(--success);
    align-self: flex-start;
}

/* Table styling */
.table-container {
    overflow-x: auto;
    border-radius: var(--border-radius-md);
    border: 1px solid var(--card-border);
    background: rgba(255, 255, 255, 0.1);
}
.theme-dark .table-container {
    background: rgba(0, 0, 0, 0.1);
}
.wage-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
    text-align: left;
}
.wage-table th {
    background: rgba(0, 0, 0, 0.02);
    padding: 12px 16px;
    font-weight: 600;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--card-border);
}
.theme-dark .wage-table th {
    background: rgba(255, 255, 255, 0.02);
}
.wage-table td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--card-border);
    vertical-align: middle;
}
.wage-table input {
    padding: 8px 12px;
    font-size: 0.875rem;
}
.total-row td {
    font-weight: 700;
    color: var(--text-primary);
    background: rgba(0, 0, 0, 0.01);
    border-bottom: none;
}
.placeholder-row td {
    text-align: center;
    color: var(--text-muted);
    padding: 24px;
}

/* Dynamic sub-periods header section */
.wage-subperiods-section {
    display: flex;
    flex-direction: column;
    gap: 14px;
}
.section-title-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.info-badge {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Buttons */
.btn {
    font-family: var(--font-family);
    font-size: 0.95rem;
    font-weight: 600;
    padding: 12px 24px;
    border-radius: var(--border-radius-md);
    border: 1px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}
.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, #4338ca 100%);
    color: #fff;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.2);
}
.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(99, 102, 241, 0.3);
}
.btn-primary:active {
    transform: translateY(0);
}
.btn-secondary {
    background: var(--secondary);
    color: #fff;
}
.btn-secondary:hover {
    background: var(--secondary-hover);
}
.btn-outline {
    background: none;
    border: 1px solid var(--card-border);
    color: var(--text-primary);
}
.btn-outline:hover {
    background: rgba(0, 0, 0, 0.02);
    border-color: var(--text-secondary);
}
.theme-dark .btn-outline:hover {
    background: rgba(255, 255, 255, 0.02);
}
.btn-sm {
    padding: 8px 16px;
    font-size: 0.85rem;
}
.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
}

/* Results Display column */
.results-column {
    display: flex;
    flex-direction: column;
    gap: 32px;
    animation: slideInRight 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideInRight {
    from { opacity: 0; transform: translateX(20px); }
    to { opacity: 1; transform: translateX(0); }
}

.result-card {
    text-align: center;
    align-items: center;
}
.result-display {
    padding: 16px 0;
    display: flex;
    align-items: baseline;
    justify-content: center;
    color: var(--primary);
}
.currency-symbol {
    font-size: 1.5rem;
    font-weight: 700;
    margin-right: 4px;
}
.amount {
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -0.03em;
}
.won-label {
    font-size: 1.25rem;
    font-weight: 700;
    margin-left: 4px;
    color: var(--text-primary);
}
.result-actions {
    display: flex;
    gap: 12px;
    width: 100%;
}
.result-actions button {
    flex: 1;
}

/* Chart display box */
.chart-container {
    width: 100%;
    height: 240px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Detailed Statement / Breakdown List */
.breakdown-list {
    display: flex;
    flex-direction: column;
    gap: 14px;
}
.breakdown-item {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    color: var(--text-secondary);
}
.breakdown-item .label {
    font-weight: 500;
}
.breakdown-item .value {
    color: var(--text-primary);
    font-weight: 600;
}
.breakdown-item.divider {
    border-top: 1px dashed var(--card-border);
    padding-top: 14px;
}
.breakdown-item .highlight {
    font-size: 1.1rem;
    color: var(--primary);
    font-weight: 700;
}
.formula-box {
    background: rgba(0, 0, 0, 0.02);
    border: 1px solid var(--card-border);
    border-radius: var(--border-radius-md);
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.theme-dark .formula-box {
    background: rgba(255, 255, 255, 0.02);
}
.formula-title {
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
}
.formula-code {
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.85rem;
    color: var(--text-secondary);
    word-break: break-all;
}

/* Placeholder columns */
.placeholder-column {
    display: none !important;
}
.placeholder-card {
    border: 1px dashed var(--card-border);
    text-align: center;
    justify-content: center;
    align-items: center;
    min-height: 400px;
    width: 100%;
    color: var(--text-muted);
}
.placeholder-icon {
    width: 64px;
    height: 64px;
    color: var(--text-muted);
    stroke-width: 1;
    margin-bottom: 16px;
}

/* Tax estimator specific layouts */
.tax-simple-bars {
    width: 100%;
    margin-top: 12px;
}
.bar-item {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.bar-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}
.bar-track {
    background: rgba(0, 0, 0, 0.05);
    height: 10px;
    border-radius: 5px;
    overflow: hidden;
}
.theme-dark .bar-track {
    background: rgba(255, 255, 255, 0.05);
}
.bar-fill {
    background: linear-gradient(90deg, var(--primary) 0%, var(--accent) 100%);
    height: 100%;
    border-radius: 5px;
    transition: width 0.8s ease-in-out;
}

/* FAQ & Legal Guidelines Layout */
.guide-container {
    max-width: 1000px;
    margin: 0 auto;
}
.guide-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}
.guide-box {
    background: rgba(0, 0, 0, 0.015);
    border: 1px solid var(--card-border);
    border-radius: var(--border-radius-md);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.theme-dark .guide-box {
    background: rgba(255, 255, 255, 0.015);
}
.guide-box h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary);
    border-bottom: 1px solid var(--card-border);
    padding-bottom: 8px;
}
.guide-box ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.5;
}
.guide-box strong {
    color: var(--text-primary);
}

/* Sidebar History Panel */
.history-sidebar {
    position: fixed;
    right: 24px;
    bottom: 24px;
    width: 320px;
    max-height: 480px;
    overflow-y: auto;
    z-index: 100;
    padding: 20px;
    display: none; /* Can toggle open or show in sidebar */
}
.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--card-border);
    padding-bottom: 10px;
    margin-bottom: 14px;
}
.sidebar-header h3 {
    font-size: 1rem;
}
.text-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 0.75rem;
    font-weight: bold;
    cursor: pointer;
}
.text-btn:hover {
    color: var(--danger);
}
.history-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.empty-history {
    font-size: 0.85rem;
    color: var(--text-muted);
    text-align: center;
    padding: 20px 0;
}
.history-item {
    padding: 12px;
    border-radius: var(--border-radius-sm);
    background: rgba(0, 0, 0, 0.02);
    border: 1px solid var(--card-border);
    cursor: pointer;
    font-size: 0.8rem;
    display: flex;
    flex-direction: column;
    gap: 4px;
    transition: var(--transition);
}
.theme-dark .history-item {
    background: rgba(255, 255, 255, 0.02);
}
.history-item:hover {
    background: rgba(99, 102, 241, 0.05);
    border-color: var(--primary);
}
.history-item .date-range {
    font-weight: 700;
    color: var(--text-primary);
}
.history-item .summary {
    display: flex;
    justify-content: space-between;
    color: var(--text-secondary);
}

/* Footer style */
.app-footer {
    text-align: center;
    padding: 24px 0;
    font-size: 0.8rem;
    color: var(--text-muted);
    border-top: 1px solid var(--card-border);
    margin-top: auto;
}
.visitor-counter-wrapper {
    display: flex;
    justify-content: center;
    margin-top: 14px;
}
.visitor-counter {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    padding: 6px 12px;
    background: rgba(255, 255, 255, 0.35);
    border: 1px solid var(--card-border);
    border-radius: 30px;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.02);
    transition: var(--transition);
}
.theme-dark .visitor-counter {
    background: rgba(15, 23, 42, 0.35);
}
.visitor-counter:hover {
    transform: translateY(-1px);
    border-color: var(--primary);
    box-shadow: 0 4px 12px var(--primary-glow);
}
.visitor-counter img {
    display: block;
    height: 20px;
    width: auto;
    border: none !important;
}

/* Simple results styling */
.btn-print-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    padding: 0;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--card-border);
    border-radius: 50%;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
}
.theme-dark .btn-print-icon {
    background: rgba(0, 0, 0, 0.15);
}
.btn-print-icon:hover {
    color: var(--primary);
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.08);
    transform: scale(1.08) translateY(-1px);
    box-shadow: 0 4px 12px var(--primary-glow);
}
.btn-print-icon:active {
    transform: scale(0.98);
}
.btn-print-icon svg {
    width: 20px;
    height: 20px;
}

/* Details Accordion */
.breakdown-details {
    padding: 0 !important;
    overflow: hidden;
    transition: all 0.3s ease;
}
.breakdown-summary {
    padding: 16px 20px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}
.breakdown-summary::-webkit-details-marker {
    display: none;
}
.breakdown-summary::after {
    content: '';
    display: inline-block;
    width: 8px;
    height: 8px;
    border-right: 2px solid var(--text-muted);
    border-bottom: 2px solid var(--text-muted);
    transform: rotate(45deg);
    transition: transform 0.2s ease;
    margin-right: 4px;
}
.breakdown-details[open] .breakdown-summary {
    border-bottom-color: var(--card-border);
    color: var(--primary);
}
.breakdown-details[open] .breakdown-summary::after {
    transform: rotate(-135deg);
    border-color: var(--primary);
}
.breakdown-details .breakdown-list {
    padding: 20px;
}
.breakdown-details .formula-box {
    margin: 0 20px 20px 20px;
}

/* Helper Utilities */
.hidden {
    display: none !important;
}

/* Responsive Breakpoints */
@media (max-width: 1024px) {
    .layout-grid {
        grid-template-columns: 1fr;
    }
    .app-container {
        padding: 20px 16px;
    }
    .history-sidebar {
        display: none !important; /* hide float history on tablets/mobile */
    }
}

@media (max-width: 768px) {
    .input-row {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    .guide-grid {
        grid-template-columns: 1fr;
    }
    .db-dc-irp-span-2 {
        grid-column: span 1 !important;
    }
    .result-actions {
        flex-direction: column;
    }
    .amount {
        font-size: 2.25rem;
    }
}

/* Print CSS Stylesheet */
@media print {
    body {
        background: #fff !important;
        color: #000 !important;
        font-size: 12pt;
    }
    .bg-glow, 
    .app-header, 
    .app-nav, 
    .form-actions, 
    .result-actions,
    .result-simple-actions,
    .btn-print-icon,
    .history-sidebar,
    .app-footer,
    #severanceForm,
    #resultsPlaceholder,
    .placeholder-column {
        display: none !important;
    }
    .app-container {
        padding: 0;
    }
    .layout-grid {
        display: block;
    }
    .card {
        background: none !important;
        border: none !important;
        box-shadow: none !important;
        padding: 0 !important;
        backdrop-filter: none !important;
    }
    #resultsColumn {
        display: block !important;
        margin-top: 20px;
    }
    .result-card {
        border: 2px solid #000 !important;
        padding: 20px !important;
        margin-bottom: 30px;
    }
    .amount-simple {
        color: #000 !important;
        font-size: 32pt !important;
    }
    .won-label-simple, .currency-symbol {
        color: #000 !important;
    }
    /* Force expand the collapsible details for a complete printed report */
    details.breakdown-details {
        display: block !important;
        border: none !important;
    }
    details.breakdown-details > summary {
        font-size: 14pt !important;
        font-weight: 700 !important;
        color: #000 !important;
        border-bottom: 2px solid #000 !important;
        padding: 10px 0 !important;
    }
    details.breakdown-details > summary::after {
        display: none !important;
    }
    details.breakdown-details > :not(summary) {
        display: block !important;
    }
    .breakdown-list {
        padding: 10px 0 !important;
    }
    .breakdown-item {
        color: #000 !important;
        font-size: 10pt !important;
        padding: 8px 0 !important;
    }
    .breakdown-item .highlight {
        color: #000 !important;
        font-size: 12pt !important;
    }
    .formula-box {
        border: 1px solid #000 !important;
        background: none !important;
        margin: 15px 0 0 0 !important;
        padding: 10px !important;
    }
    .formula-code {
        color: #000 !important;
    }
}