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

body {
    font-family: 'Inter', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    text-align: center;
    color: white;
    margin-bottom: 3rem;
}

header h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.subtitle {
    font-size: 1.2rem;
    font-weight: 300;
    opacity: 0.9;
}

main {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 3rem;
}

.timer-section {
    background: white;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    text-align: center;
}

.timer-display {
    margin-bottom: 2rem;
}

.time {
    font-size: 4rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 0.5rem;
    font-variant-numeric: tabular-nums;
}

.session-type {
    font-size: 1.2rem;
    color: #7f8c8d;
    font-weight: 500;
}

.controls {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 2rem;
}

.btn {
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.btn-primary {
    background: #3498db;
    color: white;
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
}

.btn-secondary {
    background: #e74c3c;
    color: white;
}

.btn-secondary:hover {
    background: #c0392b;
    transform: translateY(-2px);
}

.btn-tertiary {
    background: #95a5a6;
    color: white;
}

.btn-tertiary:hover {
    background: #7f8c8d;
    transform: translateY(-2px);
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

.settings {
    display: flex;
    gap: 2rem;
    justify-content: center;
}

.setting-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.setting-group label {
    font-size: 0.9rem;
    color: #7f8c8d;
    font-weight: 500;
}

.setting-group input {
    width: 80px;
    padding: 0.5rem;
    border: 2px solid #ecf0f1;
    border-radius: 5px;
    text-align: center;
    font-size: 1rem;
}

.principle-section {
    background: white;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.principle-card {
    text-align: center;
}

.principle-number {
    background: linear-gradient(135deg, #3498db, #2980b9);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    display: inline-block;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.principle-title {
    font-size: 1.8rem;
    color: #2c3e50;
    margin-bottom: 1rem;
    font-weight: 600;
}

.principle-description {
    font-size: 1rem;
    line-height: 1.6;
    color: #555;
    margin-bottom: 1.5rem;
}

.principle-quote {
    background: #f8f9fa;
    border-left: 4px solid #3498db;
    padding: 1rem;
    font-style: italic;
    color: #2c3e50;
    margin-bottom: 1.5rem;
    border-radius: 0 5px 5px 0;
}

.principle-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.stats-section {
    grid-column: 1 / -1;
    background: white;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    text-align: center;
}

.stats-section h3 {
    font-size: 1.5rem;
    color: #2c3e50;
    margin-bottom: 1.5rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: #3498db;
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 0.9rem;
    color: #7f8c8d;
    font-weight: 500;
}

.teachability-section {
    grid-column: 1 / -1;
    background: white;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.teachability-section h3 {
    font-size: 1.5rem;
    color: #2c3e50;
    margin-bottom: 1rem;
    text-align: center;
}

.assessment-intro {
    text-align: center;
    font-style: italic;
    color: #666;
    margin-bottom: 2rem;
}

.assessment-questions {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.question {
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 10px;
    border: 2px solid transparent;
    transition: all 0.3s ease;
}

.question:hover {
    border-color: #3498db;
}

.question label {
    display: flex;
    align-items: flex-start;
    gap: 0.8rem;
    cursor: pointer;
    font-size: 0.95rem;
    line-height: 1.5;
}

.question-checkbox {
    margin-top: 0.2rem;
    transform: scale(1.2);
}

.assessment-result {
    margin-top: 2rem;
    padding: 1.5rem;
    border-radius: 10px;
    text-align: center;
    font-weight: 600;
    display: none;
}

.assessment-result.show {
    display: block;
}

.assessment-result.excellent {
    background: #d4edda;
    color: #155724;
    border: 2px solid #c3e6cb;
}

.assessment-result.good {
    background: #fff3cd;
    color: #856404;
    border: 2px solid #ffeaa7;
}

.assessment-result.needs-improvement {
    background: #f8d7da;
    color: #721c24;
    border: 2px solid #f5c6cb;
}

footer {
    text-align: center;
    color: white;
    padding: 2rem 0;
}

.maxwell-quote {
    font-style: italic;
    font-size: 1.1rem;
    margin-top: 0.5rem;
    opacity: 0.9;
}

.notification {
    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: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.notification.show {
    opacity: 1;
    visibility: visible;
}

.notification-content {
    background: white;
    padding: 3rem;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    max-width: 400px;
    width: 90%;
}

.notification-content h3 {
    font-size: 2rem;
    color: #2c3e50;
    margin-bottom: 1rem;
}

.notification-content p {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 2rem;
}

/* Timer states */
.timer-running .time {
    color: #e74c3c;
}

.timer-paused .time {
    color: #f39c12;
}

.timer-break .time {
    color: #27ae60;
}

/* Responsive Design */
@media (max-width: 1024px) {
    main {
        grid-template-columns: 1fr;
    }
    
    .assessment-questions {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .time {
        font-size: 3rem;
    }
    
    .controls {
        flex-direction: column;
        align-items: center;
    }
    
    .settings {
        flex-direction: column;
        gap: 1rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .principle-actions {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .timer-section,
    .principle-section,
    .stats-section,
    .teachability-section {
        padding: 1.5rem;
    }
    
    .time {
        font-size: 2.5rem;
    }
    
    .principle-title {
        font-size: 1.4rem;
    }
}