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

body {
    background-color: #1a1a1a;
    color: #e0e0e0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    position: relative;
    margin-bottom: 3rem;
    padding: 1rem 0;
}

h1 {
    position: fixed;
    left: 2rem;
    top: 2rem;
    font-size: 1.5rem;
    font-weight: 300;
    color: #fff;
    letter-spacing: 1px;
    margin: 0;
    z-index: 100;
}

.feature {
    display: none;
    min-height: 60vh;
}

.feature.active {
    display: flex;
    flex-direction: column;
}

.feature h2 {
    display: none;
}

.form-group {
    margin-bottom: 0;
    display: flex;
    flex-direction: column;
    min-width: 120px;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    color: #ccc;
    font-weight: 500;
    font-size: 0.9rem;
}

select, input[type="number"] {
    width: 100%;
    padding: 0.5rem;
    background-color: #333;
    border: 1px solid #555;
    border-radius: 6px;
    color: #e0e0e0;
    font-size: 0.9rem;
}

select:focus, input[type="number"]:focus {
    outline: none;
    border-color: #666;
    background-color: #3a3a3a;
}

button {
    background-color: #444;
    color: #fff;
    border: none;
    padding: 0.5rem 1.5rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.2s;
    height: fit-content;
}

button:hover {
    background-color: #555;
}

.form-container {
    display: flex;
    justify-content: center;
    margin-bottom: 3rem;
}

.form-container form {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
}

.form-row {
    display: flex;
    align-items: end;
    gap: 2rem;
    flex-wrap: wrap;
    justify-content: center;
}

.result {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    font-size: 1.5rem;
    font-weight: 300;
    color: #fff;
    line-height: 1.4;
}

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

.nav-btn {
    background: none;
    border: none;
    color: #888;
    font-size: 1rem;
    cursor: pointer;
    transition: color 0.2s;
    padding: 0;
    text-decoration: none;
}

.nav-btn:hover {
    color: #ccc;
}

.nav-btn.active {
    color: #fff;
}

.chord-list {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    align-items: center;
}

.chord-card {
    background-color: #333;
    border: 1px solid #555;
    border-radius: 12px;
    padding: 1rem;
    text-align: center;
    min-width: 80px;
}

.chord-name {
    font-size: 1.4rem;
    font-weight: 400;
    color: #fff;
    margin-bottom: 0.3rem;
    letter-spacing: 1px;
}

.chord-roman {
    font-size: 0.9rem;
    color: #888;
    font-weight: 300;
}

.progression-title {
    font-size: 1rem;
    color: #ccc;
    margin-bottom: 1.5rem;
    text-align: center;
}

.instrument-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
}

.instrument-list li {
    background-color: #333;
    border: 1px solid #555;
    border-radius: 20px;
    padding: 0.5rem 1rem;
    color: #fff;
    font-size: 1rem;
    font-weight: 300;
    white-space: nowrap;
}

.strategy-text {
    font-size: 1.5rem;
    font-style: italic;
    color: #fff;
    line-height: 1.4;
    margin-bottom: 1rem;
}

.strategy-author {
    color: #888;
    font-size: 1rem;
    font-weight: 300;
}