/**
 * Calculadora de Datas Rápida - Stylesheet
 * Desenvolvido por B20 Conteúdo Digital
 * https://www.b20.com.br
 * Todos os direitos reservados
 */

/* ========================================
   CSS CUSTOM PROPERTIES
   ======================================== */
:root {
    /* Colors - Monday.com inspired */
    --primary-color: #1DB954;
    --primary-dark: #1ED760;
    --secondary-color: #191414;
    --background-light: #FFFFFF;
    --background-dark: #191414;
    --text-light: #191414;
    --text-dark: #FFFFFF;
    --border-color: #535353;
    --success-color: #1DB954;
    --error-color: #ff4757;
    --warning-color: #ffa502;
    --info-color: #3742fa;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.25rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 20px rgba(0, 0, 0, 0.15);
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Z-index */
    --z-toast: 9999;
    --z-modal: 1000;
    --z-nav: 100;
    --z-header: 90;
}

/* Dark Mode */
[data-theme="dark"] {
    --background-light: #121212;
    --background-dark: #1e1e1e;
    --text-light: #FFFFFF;
    --text-dark: #E0E0E0;
    --border-color: #555555;
}

/* ========================================
   RESET & BASE
   ======================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-light);
    background-color: var(--background-light);
    overflow-x: hidden;
    min-height: 100vh;
    padding-bottom: 80px;
}

/* ========================================
   ACCESSIBILITY
   ======================================== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* ========================================
   LOADING SCREEN
   ======================================== */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--background-light);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: var(--z-modal);
    transition: opacity var(--transition-base), visibility var(--transition-base);
}

.loading-screen.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.loading-logo {
    width: 80px;
    height: 80px;
    object-fit: contain;
    animation: pulse 1.5s ease-in-out infinite;
    filter: drop-shadow(0 4px 12px rgba(0, 0, 0, 0.2));
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.7;
        transform: scale(0.95);
    }
}

.loading-screen p {
    margin-top: var(--spacing-md);
    font-size: var(--font-size-lg);
    color: var(--text-light);
}

/* ========================================
   WELCOME GUIDE
   ======================================== */
.welcome-guide {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-modal);
    padding: var(--spacing-md);
    opacity: 1;
    visibility: visible;
    transition: opacity var(--transition-base), visibility var(--transition-base);
}

.welcome-guide.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.welcome-content {
    background: var(--background-light);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    max-width: 500px;
    width: 100%;
    position: relative;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.4s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.close-welcome {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    background: none;
    border: none;
    font-size: var(--font-size-xl);
    color: var(--text-light);
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    transition: background var(--transition-fast);
}

.close-welcome:hover {
    background: var(--border-color);
}

.welcome-content h2 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-lg);
    color: var(--text-light);
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.welcome-logo {
    height: 48px;
    width: auto;
    object-fit: contain;
    vertical-align: middle;
    filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.15));
    animation: fadeInUp 0.6s ease;
}

.welcome-content h2 i {
    color: var(--primary-color);
}

.welcome-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.feature-item {
    text-align: center;
    padding: var(--spacing-md);
}

.feature-item i {
    font-size: var(--font-size-2xl);
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

.feature-item p {
    font-size: var(--font-size-sm);
    color: var(--text-light);
}

.start-btn {
    width: 100%;
}

/* ========================================
   HEADER
   ======================================== */
.app-header {
    background: var(--background-light);
    border-bottom: 2px solid var(--border-color);
    padding: var(--spacing-md);
    position: sticky;
    top: 0;
    z-index: var(--z-header);
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
}

.app-header h1 {
    font-size: var(--font-size-xl);
    color: var(--text-light);
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.app-header h1 i {
    color: var(--primary-color);
}

.header-logo {
    height: 32px;
    width: auto;
    margin-right: var(--spacing-sm);
    object-fit: contain;
    vertical-align: middle;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
    transition: transform var(--transition-fast);
}

.app-header h1:hover .header-logo {
    transform: scale(1.05);
}

.header-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.icon-btn {
    width: 30.8px;
    height: 30.8px;
    border: none;
    background: var(--background-dark);
    color: var(--text-dark);
    border-radius: var(--radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.225rem;
    transition: all var(--transition-base);
    position: relative;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.icon-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(29, 185, 84, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.3s, height 0.3s;
}

.icon-btn:hover::before {
    width: 100%;
    height: 100%;
}

.icon-btn:hover {
    transform: scale(1.05) rotate(5deg);
    background: var(--primary-color);
    box-shadow: 0 4px 8px rgba(29, 185, 84, 0.3);
}

.icon-btn:active {
    transform: scale(0.95) rotate(0deg);
}

.lang-badge {
    position: absolute;
    bottom: -3px;
    right: -3px;
    background: var(--primary-color);
    color: white;
    font-size: 0.4375rem;
    padding: 1.4px 2.8px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

/* ========================================
   MAIN CONTENT
   ======================================== */
.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
}

.content-section {
    display: none;
    animation: fadeIn 0.3s ease;
}

.content-section.active {
    display: block;
}

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

/* ========================================
   CALCULATOR TABS
   ======================================== */
.calculator-tabs {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    overflow-x: auto;
    padding-bottom: var(--spacing-sm);
}

.tab-btn {
    flex: 1;
    min-width: 120px;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    background: var(--background-light);
    color: var(--text-light);
    border-radius: var(--radius-lg);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
    font-weight: 600;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.tab-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.tab-btn:hover::before {
    left: 100%;
}

.tab-btn i {
    font-size: var(--font-size-xl);
    transition: transform var(--transition-base);
}

.tab-btn:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(29, 185, 84, 0.15);
}

.tab-btn:hover i {
    transform: scale(1.1);
}

.tab-btn.active {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(29, 185, 84, 0.3);
}

.tab-btn.active i {
    transform: scale(1.1);
}

/* ========================================
   CALCULATOR PANELS
   ======================================== */
.calculator-panel {
    display: none;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity var(--transition-base), transform var(--transition-base);
}

.calculator-panel.active {
    display: block;
    animation: fadeInUp 0.3s ease forwards;
}

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

.calculator-form {
    background: var(--background-dark);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--text-dark);
    font-size: var(--font-size-base);
    transition: color var(--transition-base);
}

[data-theme="dark"] .form-group label {
    color: #E0E0E0;
}

.form-group:focus-within label {
    color: var(--primary-color);
    transform: translateX(4px);
    transition: all var(--transition-base);
}

.date-input,
.number-input {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: var(--font-size-lg);
    font-family: var(--font-family);
    background: var(--background-light);
    color: var(--text-light);
    transition: all var(--transition-base);
    min-height: 50px;
}

.date-input:hover,
.number-input:hover {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(29, 185, 84, 0.1);
}

.date-input:focus,
.number-input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(29, 185, 84, 0.2);
    transform: translateY(-1px);
}

.date-input:invalid:not(:placeholder-shown),
.number-input:invalid:not(:placeholder-shown) {
    border-color: var(--error-color);
    box-shadow: 0 0 0 3px rgba(255, 71, 87, 0.1);
}

.date-input:valid:not(:placeholder-shown),
.number-input:valid:not(:placeholder-shown) {
    border-color: var(--success-color);
    box-shadow: 0 0 0 3px rgba(29, 185, 84, 0.1);
}

.date-input:valid:not(:placeholder-shown)::after,
.number-input:valid:not(:placeholder-shown)::after {
    content: '✓';
    position: absolute;
    right: 12px;
    color: var(--success-color);
    font-weight: bold;
}

.form-group {
    position: relative;
}

.input-success-icon {
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--success-color);
    opacity: 0;
    transition: opacity var(--transition-base);
    pointer-events: none;
}

.input-success-icon.show {
    opacity: 1;
}

.number-input::placeholder {
    color: var(--border-color);
    opacity: 0.7;
}

.date-input::-webkit-calendar-picker-indicator,
.date-input::-webkit-inner-spin-button {
    cursor: pointer;
    opacity: 0.7;
    transition: opacity var(--transition-fast);
}

.date-input::-webkit-calendar-picker-indicator:hover,
.date-input::-webkit-inner-spin-button:hover {
    opacity: 1;
}

/* ========================================
   BUTTONS
   ======================================== */
.btn-primary,
.btn-secondary {
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    transition: all var(--transition-fast);
    min-height: 50px;
    font-family: var(--font-family);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    box-shadow: 0 2px 4px rgba(29, 185, 84, 0.2);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary-color) 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(29, 185, 84, 0.3);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 2px 4px rgba(29, 185, 84, 0.2);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-primary.loading {
    position: relative;
    color: transparent;
    pointer-events: none;
}

.btn-primary.loading::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    top: 50%;
    left: 50%;
    margin-left: -10px;
    margin-top: -10px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

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

.btn-secondary {
    background: var(--background-dark);
    color: var(--text-dark);
    border: 2px solid transparent;
}

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

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

.btn-secondary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-calculate {
    width: 100%;
    font-size: var(--font-size-lg);
}

/* ========================================
   RESULT CONTAINER
   ======================================== */
.result-container {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--background-dark);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    animation: slideIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    border: 2px solid transparent;
    transition: border-color var(--transition-base);
}

.result-container:not(.hidden) {
    border-color: var(--primary-color);
    animation: slideIn 0.4s cubic-bezier(0.16, 1, 0.3, 1), pulseGlow 2s ease-in-out;
}

@keyframes pulseGlow {
    0%, 100% {
        box-shadow: 0 4px 12px rgba(29, 185, 84, 0.2);
    }
    50% {
        box-shadow: 0 4px 20px rgba(29, 185, 84, 0.4);
    }
}

.result-container.hidden {
    display: none;
}

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

.result-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-md);
}

.result-header h3 {
    color: var(--text-dark);
    font-size: var(--font-size-lg);
}

[data-theme="dark"] .result-header h3 {
    color: #E0E0E0;
}

.result-date {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    text-align: center;
    text-shadow: 0 2px 4px rgba(29, 185, 84, 0.2);
    letter-spacing: -0.5px;
}

.result-details {
    display: grid;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.result-detail {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm);
    background: var(--background-light);
    border-radius: var(--radius-sm);
}

[data-theme="dark"] .result-detail {
    background: #2a2a2a;
}

.result-detail-label {
    color: var(--text-light);
    font-weight: 600;
}

[data-theme="dark"] .result-detail-label {
    color: #E0E0E0;
}

.result-detail-value {
    color: var(--text-light);
}

[data-theme="dark"] .result-detail-value {
    color: #E0E0E0;
}

.result-actions {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.result-actions button {
    flex: 1;
}

/* ========================================
   HISTORY
   ======================================== */
.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
}

.section-header h2 {
    font-size: var(--font-size-xl);
    color: var(--text-light);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.history-list,
.reminders-list {
    display: grid;
    gap: var(--spacing-md);
}

.history-item,
.reminder-item {
    background: var(--background-dark);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.history-item::before,
.reminder-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--primary-color);
    transform: scaleY(0);
    transition: transform var(--transition-base);
    transform-origin: bottom;
}

.history-item:hover::before,
.reminder-item:hover::before {
    transform: scaleY(1);
}

.history-item:hover,
.reminder-item:hover {
    transform: translateY(-2px) scale(1.01);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
    cursor: pointer;
}

.history-item-header,
.reminder-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.history-item-type,
.reminder-item-date {
    font-weight: 600;
    color: var(--primary-color);
    font-size: var(--font-size-sm);
}

.history-item-date {
    font-size: var(--font-size-xs);
    color: var(--border-color);
}

[data-theme="dark"] .history-item-date {
    color: #999999;
}

.history-item-content,
.reminder-item-content {
    color: var(--text-dark);
    font-size: var(--font-size-base);
}

[data-theme="dark"] .history-item-content,
[data-theme="dark"] .reminder-item-content {
    color: #E0E0E0;
}

.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--border-color);
    opacity: 0.7;
    animation: fadeIn 0.5s ease;
}

[data-theme="dark"] .empty-state {
    color: #B0B0B0;
    opacity: 0.9;
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
    color: var(--border-color);
    opacity: 0.5;
    display: block;
    transition: transform var(--transition-base);
}

[data-theme="dark"] .empty-state i {
    color: #777777;
    opacity: 0.7;
}

.empty-state:hover i {
    transform: scale(1.1);
    opacity: 0.7;
}

[data-theme="dark"] .empty-state:hover i {
    opacity: 1;
}

.empty-state p {
    font-size: var(--font-size-lg);
    margin-top: var(--spacing-md);
}

[data-theme="dark"] .empty-state p {
    color: #D0D0D0;
}

/* ========================================
   FAQ
   ======================================== */
.faq-section h2 {
    font-size: var(--font-size-xl);
    color: var(--text-light);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.faq-container {
    display: grid;
    gap: var(--spacing-md);
}

.faq-item {
    background: var(--background-dark);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.faq-question {
    width: 100%;
    padding: var(--spacing-md);
    background: none;
    border: none;
    text-align: left;
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--text-dark);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background var(--transition-fast);
    font-family: var(--font-family);
}

.faq-question:hover {
    background: var(--background-light);
}

[data-theme="dark"] .faq-question {
    color: #E0E0E0;
}

[data-theme="dark"] .faq-question:hover {
    background: #2a2a2a;
}

.faq-icon {
    font-size: var(--font-size-xl);
    color: var(--primary-color);
    transition: transform var(--transition-fast);
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 var(--spacing-md);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base), padding var(--transition-base);
}

.faq-answer.show {
    padding: var(--spacing-md);
    max-height: 500px;
}

.faq-answer p {
    color: var(--text-dark);
    line-height: 1.6;
}

[data-theme="dark"] .faq-answer p {
    color: #E0E0E0;
}

/* ========================================
   BOTTOM NAVIGATION
   ======================================== */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--background-light);
    border-top: 2px solid var(--border-color);
    display: flex;
    justify-content: space-around;
    padding: var(--spacing-sm) 0;
    z-index: var(--z-nav);
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.15);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.nav-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
    color: var(--text-light);
    text-decoration: none;
    font-size: var(--font-size-xs);
    transition: all var(--transition-base);
    border-radius: var(--radius-md);
    min-height: 60px;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.nav-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 3px;
    background: var(--primary-color);
    transition: width var(--transition-base);
    border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

.nav-item:hover::before {
    width: 80%;
}

.nav-item i {
    font-size: var(--font-size-lg);
    transition: transform var(--transition-base);
}

.nav-item:hover {
    background: rgba(29, 185, 84, 0.1);
    transform: translateY(-2px);
}

.nav-item:hover i {
    transform: scale(1.15) rotate(5deg);
    transition: transform var(--transition-fast);
}

.nav-item:active {
    transform: translateY(0);
}

.nav-item.active {
    color: var(--primary-color);
    font-weight: 600;
}

.nav-item.active::before {
    width: 80%;
}

.nav-item.active i {
    transform: scale(1.1);
}

/* ========================================
   FOOTER
   ======================================== */
.app-footer {
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--background-dark);
    color: var(--text-dark);
    margin-top: var(--spacing-xl);
}

.app-footer p {
    margin: var(--spacing-xs) 0;
    font-size: var(--font-size-sm);
}

.footer-links {
    margin-top: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: var(--font-size-sm);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.footer-links a:hover {
    text-decoration: underline;
    opacity: 0.8;
}

.footer-separator {
    color: var(--border-color);
    margin: 0 var(--spacing-xs);
}

[data-theme="dark"] .footer-separator {
    color: #666666;
}

.b20-link {
    color: var(--primary-color);
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition-fast);
}

.b20-link:hover {
    text-decoration: underline;
    transform: scale(1.05);
    display: inline-block;
}

/* ========================================
   TOAST NOTIFICATIONS
   ======================================== */
.toast {
    position: fixed;
    bottom: 100px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--background-dark);
    color: var(--text-dark);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    z-index: var(--z-toast);
    min-width: 280px;
    max-width: 90%;
    text-align: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
    visibility: visible;
}

.toast.success {
    background: linear-gradient(135deg, var(--success-color) 0%, #1ED760 100%);
    color: white;
    border-color: rgba(255, 255, 255, 0.2);
}

.toast.success::before {
    content: '✓';
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    flex-shrink: 0;
}

.toast.error {
    background: linear-gradient(135deg, var(--error-color) 0%, #ff6b7a 100%);
    color: white;
    border-color: rgba(255, 255, 255, 0.2);
}

.toast.error::before {
    content: '✕';
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    flex-shrink: 0;
}

.toast.warning {
    background: linear-gradient(135deg, var(--warning-color) 0%, #ffb84d 100%);
    color: white;
    border-color: rgba(255, 255, 255, 0.2);
}

.toast.warning::before {
    content: '⚠';
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    flex-shrink: 0;
}

.toast.info {
    background: linear-gradient(135deg, var(--info-color) 0%, #5a6bfa 100%);
    color: white;
    border-color: rgba(255, 255, 255, 0.2);
}

.toast.info::before {
    content: 'ℹ';
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    flex-shrink: 0;
}

/* ========================================
   RESPONSIVE DESIGN
   ======================================== */
@media (max-width: 768px) {
    .app-header h1 {
        font-size: var(--font-size-lg);
    }
    
    .header-logo {
        height: 28px;
    }
    
    .welcome-logo {
        height: 40px;
    }
    
    .loading-logo {
        width: 60px;
        height: 60px;
    }
    
    .calculator-tabs {
        flex-direction: column;
    }
    
    .tab-btn {
        flex-direction: row;
        justify-content: flex-start;
    }
    
    .welcome-features {
        grid-template-columns: 1fr;
    }
}

@media (min-width: 769px) {
    .calculator-form {
        max-width: 600px;
        margin: 0 auto;
    }
    
    .result-container {
        max-width: 600px;
        margin-left: auto;
        margin-right: auto;
    }
    
    .history-list,
    .reminders-list {
        grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    }
}

@media (min-width: 1024px) {
    .bottom-nav {
        max-width: 800px;
        left: 50%;
        transform: translateX(-50%);
        border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    }
}

/* ========================================
   PRINT STYLES
   ======================================== */
@media print {
    .app-header,
    .bottom-nav,
    .header-actions,
    .result-actions {
        display: none;
    }
    
    body {
        padding-bottom: 0;
    }
}