/* ===== CSS Variables & Design Tokens ===== */
:root {
    /* Colors */
    --color-primary: #6366f1;
    --color-primary-dark: #4f46e5;
    --color-primary-light: #818cf8;
    
    --color-success: #10b981;
    --color-success-light: #d1fae5;
    --color-success-dark: #059669;
    
    --color-warning: #f59e0b;
    --color-warning-light: #fef3c7;
    --color-warning-dark: #d97706;
    
    --color-danger: #ef4444;
    --color-danger-light: #fee2e2;
    --color-danger-dark: #dc2626;
    
    --color-info: #3b82f6;
    --color-info-light: #dbeafe;
    --color-info-dark: #2563eb;
    
    /* Neutrals */
    --color-bg: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-bg-tertiary: #334155;
    --color-surface: #1e293b;
    --color-surface-hover: #334155;
    --color-border: #475569;
    
    --color-text: #f8fafc;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    
    /* Typography */
    --font-family: 'Rubik', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.15);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
}

/* ===== Base Styles ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    background-image: 
        radial-gradient(ellipse at top, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at bottom right, rgba(16, 185, 129, 0.05) 0%, transparent 50%);
}

/* ===== App Container ===== */
.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-4);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Header ===== */
.header {
    text-align: center;
    padding: var(--space-8) 0;
    margin-bottom: var(--space-6);
    position: relative;
}

.header-content h1 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-success));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--space-2);
}

.subtitle {
    color: var(--color-text-secondary);
    font-size: var(--font-size-lg);
}

.month-selector {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-4);
    margin-top: var(--space-6);
}

.month-nav {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    width: 44px;
    height: 44px;
    border-radius: var(--radius-full);
    cursor: pointer;
    font-size: var(--font-size-lg);
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
}

.month-nav:hover {
    background: var(--color-primary);
    border-color: var(--color-primary);
    transform: scale(1.05);
}

.current-month {
    font-size: var(--font-size-xl);
    font-weight: 600;
    min-width: 200px;
    color: var(--color-text);
}

/* ===== Main Content ===== */
.main-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-6);
    flex: 1;
}

@media (max-width: 900px) {
    .main-content {
        grid-template-columns: 1fr;
    }
}

/* ===== Section Styles ===== */
.calendar-section,
.workdays-section,
.results-section {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
}

.results-section {
    grid-column: 1 / -1;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-5);
    padding-bottom: var(--space-4);
    border-bottom: 1px solid var(--color-border);
}

.section-header h2 {
    font-size: var(--font-size-xl);
    font-weight: 600;
}

.hint {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.badge {
    background: var(--color-primary);
    color: white;
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

/* ===== Calendar ===== */
.calendar-container {
    user-select: none;
}

.calendar-header {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: var(--space-1);
    margin-bottom: var(--space-2);
}

.calendar-header span {
    text-align: center;
    font-weight: 600;
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    padding: var(--space-2);
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: var(--space-1);
}

.calendar-day {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-weight: 500;
    transition: all var(--transition-fast);
    background: var(--color-bg-secondary);
    border: 2px solid transparent;
    position: relative;
}

.calendar-day:hover:not(.empty):not(.selected) {
    background: var(--color-surface-hover);
    border-color: var(--color-primary);
    transform: scale(1.05);
}

.calendar-day.empty {
    background: transparent;
    cursor: default;
}

.calendar-day.selected {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    border-color: var(--color-primary-light);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.4);
}

.calendar-day.selected::after {
    content: '✓';
    position: absolute;
    top: 2px;
    right: 4px;
    font-size: 10px;
}

.calendar-day.today {
    border-color: var(--color-warning);
}

/* ===== Workdays List ===== */
.workdays-list {
    max-height: 400px;
    overflow-y: auto;
    padding-left: var(--space-2);
}

.workdays-list::-webkit-scrollbar {
    width: 6px;
}

.workdays-list::-webkit-scrollbar-track {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-full);
}

.workdays-list::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: var(--radius-full);
}

.empty-state {
    text-align: center;
    padding: var(--space-10);
    color: var(--color-text-muted);
}

.empty-icon {
    font-size: 48px;
    display: block;
    margin-bottom: var(--space-3);
    opacity: 0.5;
}

.workday-item {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-3) var(--space-4);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-2);
    transition: all var(--transition-base);
    animation: slideIn 0.2s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.workday-item:hover {
    background: var(--color-surface-hover);
}

.workday-date {
    font-weight: 600;
    min-width: 80px;
    color: var(--color-primary-light);
}

.workday-hours {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    flex: 1;
}

.hours-input {
    width: 60px;
    padding: var(--space-2);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-bg);
    color: var(--color-text);
    text-align: center;
    font-family: inherit;
    font-size: var(--font-size-base);
    transition: all var(--transition-fast);
}

.hours-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.hours-label {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

.workday-pay {
    font-weight: 600;
    color: var(--color-success);
}

.remove-btn {
    background: transparent;
    border: none;
    color: var(--color-danger);
    cursor: pointer;
    padding: var(--space-2);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    font-size: var(--font-size-lg);
}

.remove-btn:hover {
    background: var(--color-danger-light);
    color: var(--color-danger-dark);
}

/* ===== Results Grid ===== */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-4);
}

.result-card {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-5);
    border-radius: var(--radius-lg);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

.result-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.result-card.large {
    grid-column: span 1;
    padding: var(--space-6);
}

@media (min-width: 600px) {
    .result-card.large {
        grid-column: span 2;
    }
}

@media (min-width: 900px) {
    .result-card.large {
        grid-column: span 1;
    }
}

.result-icon {
    font-size: 2rem;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-lg);
    flex-shrink: 0;
}

.result-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.result-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.result-value {
    font-size: var(--font-size-2xl);
    font-weight: 700;
}

.result-note {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
}

/* Card Types */
.result-card.info .result-icon {
    background: var(--color-info-light);
}

.result-card.info .result-value {
    color: var(--color-info);
}

.result-card.highlight {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(99, 102, 241, 0.05));
    border-color: var(--color-primary);
}

.result-card.highlight .result-icon {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
}

.result-card.highlight .result-value {
    color: var(--color-primary-light);
}

.result-card.warning .result-icon {
    background: var(--color-warning-light);
}

.result-card.warning .result-value {
    color: var(--color-warning);
}

.result-card.expense {
    border-color: rgba(239, 68, 68, 0.3);
}

.result-card.expense .result-icon {
    background: var(--color-danger-light);
}

.result-card.expense .result-value {
    color: var(--color-danger);
}

.result-card.expense.large {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.1), rgba(239, 68, 68, 0.05));
}

.result-card.income {
    border-color: rgba(16, 185, 129, 0.3);
}

.result-card.income .result-icon {
    background: var(--color-success-light);
}

.result-card.income .result-value {
    color: var(--color-success);
}

.result-card.income.large {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(16, 185, 129, 0.05));
}

/* ===== Footer ===== */
.footer {
    text-align: center;
    padding: var(--space-6) 0;
    margin-top: var(--space-8);
    border-top: 1px solid var(--color-border);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

/* ===== Responsive ===== */
@media (max-width: 600px) {
    .header-content h1 {
        font-size: var(--font-size-2xl);
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-2);
    }
    
    .workday-item {
        flex-wrap: wrap;
    }
    
    .workday-pay {
        width: 100%;
        text-align: left;
        margin-top: var(--space-2);
    }
    
    .result-card {
        padding: var(--space-4);
    }
    
    .result-icon {
        width: 48px;
        height: 48px;
        font-size: 1.5rem;
    }
    
    .result-value {
        font-size: var(--font-size-xl);
    }
}

/* ===== Animations ===== */
@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

.calculating .result-value {
    animation: pulse 0.5s ease;
}

/* ===== Header Actions ===== */
.header-actions {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
    margin-top: var(--space-4);
}

.sync-status {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    transition: all var(--transition-base);
}

.sync-status.syncing {
    border-color: var(--color-warning);
    background: rgba(245, 158, 11, 0.1);
}

.sync-status.syncing .sync-icon {
    animation: rotate 2s linear infinite;
}

.sync-status.error {
    border-color: var(--color-danger);
    background: rgba(239, 68, 68, 0.1);
    color: var(--color-danger);
}

.sync-status.success {
    border-color: var(--color-success);
    background: rgba(16, 185, 129, 0.1);
    color: var(--color-success);
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.logout-btn {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    cursor: pointer;
    font-size: var(--font-size-lg);
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
}

.logout-btn:hover {
    background: var(--color-danger);
    border-color: var(--color-danger);
    transform: scale(1.05);
}

/* ===== Modal ===== */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(4px);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.show {
    display: flex;
    animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-content {
    background: var(--color-surface);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-xl);
    max-width: 400px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    animation: slideUp 0.3s ease;
}

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

.modal-header {
    padding: var(--space-6);
    border-bottom: 1px solid var(--color-border);
    text-align: center;
}

.modal-header h2 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--space-2);
}

.modal-subtitle {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

.modal-body {
    padding: var(--space-6);
}

.modal-footer {
    padding: var(--space-6);
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: flex-end;
    gap: var(--space-3);
}

.input-group {
    position: relative;
    margin-bottom: var(--space-4);
}

.input-group label {
    display: block;
    margin-bottom: var(--space-2);
    font-weight: 500;
    color: var(--color-text);
}

.pin-input {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    padding-left: 50px; /* Make room for toggle button */
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    color: var(--color-text);
    font-size: var(--font-size-lg);
    font-family: inherit;
    transition: all var(--transition-fast);
    text-align: center;
    letter-spacing: 0.2em;
}

.pin-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.toggle-pin {
    position: absolute;
    left: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: transparent;
    border: none;
    cursor: pointer;
    font-size: var(--font-size-lg);
    padding: var(--space-2);
    line-height: 1;
    transition: all var(--transition-fast);
}

.toggle-pin:hover {
    transform: translateY(-50%) scale(1.1);
}

.modal-hint {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    text-align: center;
}

.btn {
    padding: var(--space-3) var(--space-6);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-base);
    border: none;
    font-family: inherit;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

/* ===== Toast Notifications ===== */
.toast-container {
    position: fixed;
    bottom: var(--space-6);
    left: 50%;
    transform: translateX(-50%);
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    max-width: 90%;
    width: 400px;
}

.toast {
    padding: var(--space-4) var(--space-5);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    display: flex;
    align-items: center;
    gap: var(--space-3);
    animation: toastSlideIn 0.3s ease;
}

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

.toast.toast-success {
    border-color: var(--color-success);
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(16, 185, 129, 0.05));
}

.toast.toast-error {
    border-color: var(--color-danger);
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.1), rgba(239, 68, 68, 0.05));
}

.toast.toast-info {
    border-color: var(--color-info);
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(59, 130, 246, 0.05));
}

.toast-icon {
    font-size: var(--font-size-2xl);
}

.toast-message {
    flex: 1;
    font-size: var(--font-size-sm);
}

.toast-close {
    background: transparent;
    border: none;
    color: var(--color-text-muted);
    cursor: pointer;
    padding: var(--space-1);
    font-size: var(--font-size-lg);
    transition: all var(--transition-fast);
}

.toast-close:hover {
    color: var(--color-text);
    transform: scale(1.1);
}

/* ===== Responsive Modal ===== */
@media (max-width: 600px) {
    .modal-content {
        margin: var(--space-4);
    }
    
    .header-actions {
        flex-wrap: wrap;
    }
}