body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    color: #333;
}

header {
    text-align: center;
    margin-bottom: 2rem;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15);
    background-color: #ffffff;
}

#content-container>div {
    padding: 20px;
    background-color: rgba(255, 255, 255, 0.8);
    box-shadow: 0 2px 3px rgba(0, 0, 0, 0.05);
}

header h1 {
    text-align: start;
    margin-bottom: 1rem;
    color: #2c3e50;
}

footer {
    text-align: center;
    padding: 1rem;
    color: #666;
    opacity: 0.8;
}

.horizontal-nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: row;
    background-color: transparent;
}

.nav-item {
    color: black;
    text-decoration: none;
    padding: 10px;
    transition: color 0.3s;
}

.nav-item.active {
    color: rgb(88, 88, 220);
}

.container {
    display: flex;
    gap: 2rem;
}

.chords {
    flex: 1;
    padding: 1.5rem;
}

.ul-chord {
    list-style-type: none;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.li-chord {
    margin-bottom: 1rem;
}

.choose-chord {
    text-decoration: none;
    color: #495057;
    background-color: #e9ecef;
    display: block;
    padding: 0.6rem 1rem;
    border-radius: 12px;
    transition: all 0.3s ease;
    text-align: center;
    font-weight: 500;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.choose-chord:hover {
    background-color: #dee2e6;
    transform: translateY(-1px);
    box-shadow: 0 2px 3px rgba(0, 0, 0, 0.1);
}

main {
    flex: 3;
    background-color: #fff;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.chord { float: left; padding-top: 8px;}

.chordname {
  width: 80%;
  margin: auto;
  font-family: "Marvel", cursive;
  font-size: 20px;
  text-align: center;
}

.chord-update-info {
    color: #28a745;
    font-size: 16px;
    font-weight: bold;
    margin-bottom: 1rem;
    padding: 10px;
    background-color: #f8f9fa;
    border-left: 4px solid #28a745;
    border-radius: 4px;
}