* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
    color: #333;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.calculator-container {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 900px;
    overflow: hidden;
}

.header {
    background: linear-gradient(to right, #4b6cb7, #182848);
    color: white;
    padding: 25px;
    text-align: center;
    position: relative;
}

.header h1 {
    font-size: 2.2rem;
    margin-bottom: 10px;
}

.header p {
    opacity: 0.9;
}

.fullscreen-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s;
}

.fullscreen-btn:hover {
    background: rgba(255, 255, 255, 0.3);
}

.tabs {
    display: flex;
    background: #f0f0f0;
    border-bottom: 1px solid #ddd;
}

.tab {
    padding: 15px 25px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
    text-align: center;
    flex: 1;
}

.tab.active {
    background: white;
    border-bottom: 3px solid #4b6cb7;
    color: #4b6cb7;
}

.tab-content {
    display: none;
    padding: 30px;
}

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

.converter {
    display: flex;
    flex-direction: column;
    gap: 20px;
    max-width: 500px;
    margin: 0 auto;
}

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

label {
    font-weight: 600;
    color: #444;
}

input, select {
    padding: 12px 15px;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s;
}

input:focus, select:focus {
    outline: none;
    border-color: #4b6cb7;
    box-shadow: 0 0 0 3px rgba(75, 108, 183, 0.2);
}

.btn {
    background: #4b6cb7;
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn:hover {
    background: #3a559d;
    transform: translateY(-2px);
}

.result {
    margin-top: 20px;
    padding: 15px;
    border-radius: 8px;
    background: #f8f9fa;
    text-align: center;
    font-size: 1.2rem;
    font-weight: 600;
    color: #4b6cb7;
}

.course-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin: 20px 0;
}

.course {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr auto;
    gap: 10px;
    align-items: center;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
}

.course-header {
    font-weight: 600;
    color: #444;
    padding: 0 15px;
}

.add-course {
    margin: 20px 0;
    text-align: center;
}

.action-btn {
    background: transparent;
    border: none;
    color: #ff4757;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s;
}

.action-btn:hover {
    color: #ff2e43;
    transform: scale(1.1);
}

.summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.summary-card {
    background: linear-gradient(135deg, #4b6cb7 0%, #3a559d 100%);
    color: white;
    padding: 20px;
    border-radius: 12px;
    text-align: center;
}

.summary-card h3 {
    font-size: 1rem;
    margin-bottom: 10px;
    opacity: 0.9;
}

.summary-card p {
    font-size: 1.8rem;
    font-weight: 700;
}

@media (max-width: 768px) {
    .course {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .tabs {
        flex-direction: column;
    }
    
    .summary {
        grid-template-columns: 1fr;
    }
}

.instructions {
    background: #e3f2fd;
    padding: 15px;
    border-radius: 8px;
    margin: 20px 0;
    font-size: 0.9rem;
}

.instructions h3 {
    margin-bottom: 10px;
    color: #4b6cb7;
}

.instructions ul {
    padding-left: 20px;
}

.instructions li {
    margin-bottom: 5px;
}