/* CSS Variables for consistent theming */
:root {
    --primary-color: #7868E6;
    --secondary-color: #B8B5FF;
    --accent-color: #FFB4B4;
    --background-light: #EDEEF7;
    --background-accent: #E4FBFF;
    --text-primary: #2D3748;
    --text-secondary: #4A5568;
    --text-muted: #718096;
    --border-color: #E2E8F0;
    --success-color: #48BB78;
    --warning-color: #ED8936;
    --error-color: #F56565;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

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

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--background-light);
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(120, 104, 230, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(184, 181, 255, 0.1) 0%, transparent 50%);
    min-height: 100vh;
    position: relative;
}

/* Paper Texture Effect */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        repeating-linear-gradient(
            45deg,
            transparent,
            transparent 2px,
            rgba(255, 255, 255, 0.1) 2px,
            rgba(255, 255, 255, 0.1) 4px
        );
    pointer-events: none;
    z-index: -1;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-md);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo-icon {
    font-size: 2rem;
    filter: drop-shadow(0 0 10px rgba(255, 255, 255, 0.3));
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    transition: var(--transition);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: white;
    transition: var(--transition);
}

.nav-link.active::after {
    width: 80%;
}

/* Main Content */
.main {
    padding: 2rem 0;
    min-height: calc(100vh - 200px);
}

.section {
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

.section.active {
    display: block;
}

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

.section-title {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    text-align: center;
    color: var(--primary-color);
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

/* Cards */
.card {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

/* Dashboard Grid */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

/* Energy Card */
.energy-card {
    text-align: center;
    background: linear-gradient(135deg, var(--background-accent), white);
}

.energy-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin: 1rem 0;
}

.energy-value {
    font-size: 3rem;
    font-weight: bold;
    color: var(--primary-color);
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

.energy-label {
    font-size: 1.2rem;
    color: var(--text-muted);
}

.energy-status {
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: bold;
    margin-top: 1rem;
    display: inline-block;
}

.energy-status.low {
    background: var(--error-color);
    color: white;
}

.energy-status.medium {
    background: var(--warning-color);
    color: white;
}

.energy-status.high {
    background: var(--success-color);
    color: white;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
    gap: 1rem;
    text-align: center;
}

.stat-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Chart Card */
.chart-card canvas {
    max-width: 100%;
    height: auto;
}

/* Activities List */
.activities-list {
    max-height: 300px;
    overflow-y: auto;
}

.activity-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.activity-item:hover {
    background: var(--background-light);
}

.activity-item:last-child {
    border-bottom: none;
}

.activity-info {
    flex: 1;
}

.activity-name {
    font-weight: bold;
    color: var(--text-primary);
}

.activity-time {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.activity-energy {
    font-weight: bold;
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.9rem;
}

/* Form Styles */
.energy-form {
    max-width: 600px;
    margin: 0 auto;
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: var(--text-primary);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: white;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(120, 104, 230, 0.1);
}

.form-input:invalid {
    border-color: var(--error-color);
}

.form-help {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* Energy Slider */
.energy-slider {
    width: 100%;
    height: 8px;
    border-radius: 4px;
    background: linear-gradient(90deg, var(--error-color), var(--warning-color), var(--success-color));
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
}

.energy-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: white;
    border: 3px solid var(--primary-color);
    cursor: pointer;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.energy-slider::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

.energy-slider::-moz-range-thumb {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: white;
    border: 3px solid var(--primary-color);
    cursor: pointer;
    box-shadow: var(--shadow-md);
}

.energy-slider-value {
    float: right;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: bold;
}

/* Activity Tags */
.activity-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag-btn {
    background: var(--background-light);
    border: 2px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
    color: var(--text-primary);
}

.tag-btn:hover {
    border-color: var(--primary-color);
    background: var(--secondary-color);
    color: white;
    transform: translateY(-2px);
}

.tag-btn.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-md);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: bold;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

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

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

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

.btn-secondary:hover {
    background: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.btn-danger {
    background: var(--error-color);
    color: white;
}

.btn-danger:hover {
    background: #E53E3E;
    transform: translateY(-2px);
}

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

.btn-loading {
    display: none;
}

.btn.loading .btn-text {
    display: none;
}

.btn.loading .btn-loading {
    display: inline;
}

/* Insights Grid */
.insights-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.insight-card {
    background: linear-gradient(135deg, white, var(--background-accent));
}

.insights-content {
    max-height: 300px;
    overflow-y: auto;
}

.insight-item {
    padding: 1rem;
    margin-bottom: 1rem;
    background: white;
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.insight-title {
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.insight-description {
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Data Actions */
.data-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
}

/* No Data State */
.no-data {
    text-align: center;
    color: var(--text-muted);
    font-style: italic;
    padding: 2rem;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    color: white;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top: 4px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1001;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.toast {
    background: white;
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    border-left: 4px solid var(--primary-color);
    max-width: 300px;
    animation: slideIn 0.3s ease-out;
}

.toast.success {
    border-left-color: var(--success-color);
}

.toast.error {
    border-left-color: var(--error-color);
}

.toast.warning {
    border-left-color: var(--warning-color);
}

@keyframes slideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer a {
    color: var(--secondary-color);
    text-decoration: none;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 0.5rem;
    }
    
    .header .container {
        flex-direction: column;
        text-align: center;
    }
    
    .nav-list {
        flex-wrap: wrap;
        gap: 1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .insights-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .data-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .energy-form {
        padding: 1rem;
    }
    
    .activity-tags {
        justify-content: center;
    }
    
    .toast-container {
        right: 10px;
        left: 10px;
    }
    
    .toast {
        max-width: none;
    }
}

@media (max-width: 480px) {
    .energy-value {
        font-size: 2rem;
    }
    
    .stat-value {
        font-size: 1.2rem;
    }
    
    .btn {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .form-input,
    .form-textarea {
        padding: 0.5rem;
    }
    
    .card {
        padding: 1rem;
    }
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .btn,
    .loading-overlay,
    .toast-container {
        display: none;
    }
    
    .section {
        display: block !important;
    }
    
    .card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ccc;
    }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #000080;
        --secondary-color: #4B0082;
        --text-primary: #000000;
        --text-secondary: #333333;
        --border-color: #000000;
    }
    
    .card {
        border: 2px solid var(--border-color);
    }
    
    .btn {
        border: 2px solid currentColor;
    }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus Styles for Accessibility */
*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn:focus,
.form-input:focus,
.form-textarea:focus,
.energy-slider:focus,
.tag-btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Skip Link for Screen Readers */
.skip-link {
    position: absolute;
    top: -40px;
    left: 6px;
    background: var(--primary-color);
    color: white;
    padding: 8px;
    text-decoration: none;
    border-radius: 4px;
    z-index: 1000;
}

.skip-link:focus {
    top: 6px;
}