/* CSS Custom Properties */
:root {
    --primary-color: #7868E6;
    --secondary-color: #B8B5FF;
    --accent-color: #EDEEF7;
    --light-blue: #E4FBFF;
    --error-color: #FFB4B4;
    
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --border-radius: 12px;
    --shadow: 0 4px 20px rgba(120, 104, 230, 0.15);
    --transition: all 0.3s ease;
    
    --paper-texture: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="paper" patternUnits="userSpaceOnUse" width="100" height="100"><rect width="100" height="100" fill="%23EDEEF7"/><circle cx="20" cy="20" r="1" fill="%23B8B5FF" opacity="0.3"/><circle cx="80" cy="40" r="1" fill="%23B8B5FF" opacity="0.2"/><circle cx="40" cy="80" r="1" fill="%23B8B5FF" opacity="0.4"/></pattern></defs><rect width="100" height="100" fill="url(%23paper)"/></svg>');
}

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

body {
    font-family: var(--font-family);
    background: var(--accent-color);
    background-image: var(--paper-texture);
    color: #333;
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header Styles */
.header {
    text-align: center;
    margin-bottom: 40px;
    padding: 30px 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    color: white;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(180deg); }
}

.app-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
    position: relative;
    z-index: 1;
}

.app-subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
    position: relative;
    z-index: 1;
}

/* Main Content */
.main-content {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr;
    gap: 30px;
    margin-bottom: 40px;
}

/* Card Styles */
.timer-card,
.session-card,
.benefits-card,
.progress-card,
.sessions-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.timer-card::before,
.session-card::before,
.benefits-card::before,
.progress-card::before,
.sessions-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.timer-card:hover,
.session-card:hover,
.benefits-card:hover,
.progress-card:hover,
.sessions-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(120, 104, 230, 0.2);
}

/* Timer Styles */
.timer-display {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    background: linear-gradient(135deg, var(--light-blue), var(--accent-color));
    border-radius: var(--border-radius);
    border: 2px solid var(--secondary-color);
}

.time-unit {
    font-size: 4rem;
    font-weight: 700;
    color: var(--primary-color);
    text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
    display: inline-block;
    min-width: 120px;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.time-separator {
    font-size: 3rem;
    color: var(--secondary-color);
    margin: 0 10px;
    animation: blink 1s infinite;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0.3; }
}

.timer-controls {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.timer-status {
    text-align: center;
    font-size: 1.1rem;
    color: var(--primary-color);
    font-weight: 600;
}

/* Button Styles */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    min-width: 120px;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255,255,255,0.3);
    border-radius: 50%;
    transition: width 0.6s, height 0.6s, top 0.6s, left 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
    top: -150px;
    left: -150px;
}

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

.btn-primary:hover {
    background: #6952d9;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(120, 104, 230, 0.3);
}

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

.btn-secondary:hover {
    background: #a69aff;
    transform: translateY(-2px);
}

.btn-danger {
    background: var(--error-color);
    color: #8b0000;
}

.btn-danger:hover {
    background: #ff9999;
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
}

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

.btn:disabled:hover {
    transform: none;
    box-shadow: none;
}

.btn-icon {
    font-size: 1.2rem;
}

/* Form Styles */
.session-form {
    display: grid;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group label {
    font-weight: 600;
    color: var(--primary-color);
}

.form-group input,
.form-group textarea {
    padding: 12px;
    border: 2px solid var(--secondary-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--light-blue);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(120, 104, 230, 0.1);
    transform: translateY(-2px);
}

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

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

/* Benefits Chart */
.benefits-container {
    text-align: center;
    margin-bottom: 20px;
}

#benefits-chart {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.benefits-legend {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    border: 2px solid #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

/* Progress Stats */
.progress-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-item {
    text-align: center;
    padding: 20px;
    background: var(--light-blue);
    border-radius: var(--border-radius);
    border: 2px solid var(--secondary-color);
    transition: var(--transition);
}

.stat-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.stat-label {
    display: block;
    font-size: 0.9rem;
    color: var(--primary-color);
    margin-bottom: 8px;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

/* Milestones */
.progress-milestones h3 {
    margin-bottom: 20px;
    color: var(--primary-color);
    text-align: center;
}

.milestone-list {
    display: grid;
    gap: 15px;
}

.milestone-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 15px;
    background: var(--accent-color);
    border-radius: var(--border-radius);
    border: 2px solid var(--secondary-color);
    transition: var(--transition);
}

.milestone-item:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow);
}

.milestone-item.completed {
    background: var(--light-blue);
    border-color: var(--primary-color);
}

.milestone-icon {
    font-size: 2rem;
    min-width: 50px;
    text-align: center;
}

.milestone-info {
    flex: 1;
}

.milestone-info h4 {
    margin-bottom: 5px;
    color: var(--primary-color);
}

.milestone-info p {
    font-size: 0.9rem;
    color: #666;
}

.milestone-status {
    font-size: 0.9rem;
    font-weight: 600;
    padding: 5px 10px;
    border-radius: 20px;
    background: var(--secondary-color);
    color: white;
    min-width: 80px;
    text-align: center;
}

.milestone-status.completed {
    background: var(--primary-color);
}

/* Sessions List */
.sessions-list {
    max-height: 400px;
    overflow-y: auto;
    margin-bottom: 20px;
}

.session-item {
    padding: 15px;
    border: 2px solid var(--secondary-color);
    border-radius: var(--border-radius);
    margin-bottom: 10px;
    background: var(--light-blue);
    transition: var(--transition);
}

.session-item:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow);
}

.session-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
    flex-wrap: wrap;
    gap: 10px;
}

.session-name {
    font-weight: 600;
    color: var(--primary-color);
}

.session-duration {
    font-size: 0.9rem;
    color: #666;
}

.session-date {
    font-size: 0.9rem;
    color: #666;
}

.session-notes {
    font-size: 0.9rem;
    color: #555;
    font-style: italic;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.7);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    color: white;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 5px solid rgba(255,255,255,0.3);
    border-top: 5px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

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

/* Footer */
.footer {
    text-align: center;
    padding: 20px;
    background: var(--primary-color);
    color: white;
    border-radius: var(--border-radius);
    margin-top: auto;
}

.footer p {
    margin: 0;
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .app-container {
        padding: 10px;
    }
    
    .app-title {
        font-size: 2rem;
    }
    
    .time-unit {
        font-size: 2.5rem;
        min-width: 80px;
    }
    
    .time-separator {
        font-size: 2rem;
        margin: 0 5px;
    }
    
    .timer-controls {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        max-width: 200px;
    }
    
    .progress-stats {
        grid-template-columns: 1fr;
    }
    
    .milestone-item {
        flex-direction: column;
        text-align: center;
    }
    
    .session-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .timer-card,
    .session-card,
    .benefits-card,
    .progress-card,
    .sessions-card {
        padding: 20px;
    }
}

@media (max-width: 480px) {
    .time-unit {
        font-size: 2rem;
        min-width: 60px;
    }
    
    .time-separator {
        font-size: 1.5rem;
    }
    
    .app-title {
        font-size: 1.5rem;
    }
    
    .app-subtitle {
        font-size: 1rem;
    }
}

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

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #000080;
        --secondary-color: #4040ff;
        --accent-color: #f0f0f0;
        --light-blue: #e0e0ff;
        --error-color: #ff0000;
    }
}

/* Focus styles for accessibility */
button:focus,
input:focus,
textarea:focus {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* Print styles */
@media print {
    .timer-controls,
    .btn,
    .loading-overlay {
        display: none !important;
    }
    
    .app-container {
        max-width: none;
        padding: 0;
    }
    
    .timer-card,
    .session-card,
    .benefits-card,
    .progress-card,
    .sessions-card {
        box-shadow: none;
        border: 2px solid #000;
        page-break-inside: avoid;
    }
}