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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f9f4e3;
    min-height: 100vh;
    padding: 20px;
}

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

h1 {
    text-align: center;
    color: #2d3138;
    margin-bottom: 30px;
    font-size: 2.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.exercises-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 30px;
    margin-bottom: 30px;
}

.exercise-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    transition: transform 0.3s ease;
}

.exercise-card:hover {
    transform: translateY(-5px);
}

.exercise-title {
    color: #2d3138;
    font-size: 1.5rem;
    margin-bottom: 20px;
    border-bottom: 2px solid #e45252;
    padding-bottom: 10px;
}

.formula-box {
    background: #f9f4e3;
    border-left: 4px solid #e45252;
    padding: 15px;
    margin: 15px 0;
    font-family: 'Courier New', monospace;
    border-radius: 5px;
}

.input-group {
    margin: 15px 0;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
    color: #2d3138;
}

input {
    width: 100%;
    padding: 12px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

input:focus {
    outline: none;
    border-color: #2d3138;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.btn {
    background: #2d3138;
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    margin: 10px 5px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(61, 61, 61, 0.4);
}

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

.result-box {
    background: #2d3138;
    color: white;
    padding: 20px;
    border-radius: 10px;
    margin-top: 20px;
    display: none;
    animation: slideIn 0.5s ease;
}

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

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.steps {
    background: #fff;
    border-radius: 8px;
    padding: 15px;
    margin-top: 15px;
    color: #2d3138;
}

.step {
    margin: 10px 0;
    padding: 8px;
    border-left: 3px solid #e45252;
    padding-left: 15px;
}

.math-notation {
    font-family: 'Times New Roman', serif;
    font-style: italic;
}

.highlight {
    background: #e45252;
    padding: 5px 10px;
    border-radius: 4px;
    font-weight: bold;
}