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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea, #764ba2);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 10px;
    padding: 30px;
    width: 800px;
    max-width: 100%;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

h1 {
    color: #333;
    margin-bottom: 20px;
    text-align: center;
    border-bottom: 2px solid #667eea;
    padding-bottom: 10px;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
    color: #555;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 14px;
}

.radio-group {
    display: flex;
    gap: 20px;
    margin-top: 5px;
}

.radio-group label {
    display: inline;
    font-weight: normal;
}

.button-group {
    display: flex;
    gap: 10px;
    margin: 20px 0;
}

button {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
    background: #f0f0f0;
    color: #333;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

button:active {
    transform: translateY(0);
}

#addBtn {
    background: #667eea;
    color: white;
}

#addBtn:hover {
    background: #5a6fd6;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

#saveBtn {
    background: #4CAF50;
    color: white;
}

#saveBtn:hover {
    background: #45a049;
    box-shadow: 0 5px 15px rgba(76, 175, 80, 0.4);
}

#sortBtn {
    background: #ff9800;
    color: white;
}

#sortBtn:hover {
    background: #fb8c00;
    box-shadow: 0 5px 15px rgba(255, 152, 0, 0.4);
}

/* Ripple effect */
button::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 5px;
    height: 5px;
    background: rgba(255, 255, 255, 0.5);
    opacity: 0;
    border-radius: 100%;
    transform: scale(1, 1) translate(-50%, -50%);
    transform-origin: 50% 50%;
}

button:focus:not(:active)::after {
    animation: ripple 0.6s ease-out;
}

@keyframes ripple {
    0% {
        transform: scale(0, 0);
        opacity: 0.5;
    }
    100% {
        transform: scale(30, 30);
        opacity: 0;
    }
}

.progress-bar {
    background: #f0f0f0;
    border-radius: 20px;
    height: 25px;
    margin: 20px 0;
    overflow: hidden;
    box-shadow: inset 0 2px 5px rgba(0,0,0,0.1);
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 13px;
    font-weight: bold;
    transition: width 0.5s ease;
    text-shadow: 0 1px 2px rgba(0,0,0,0.2);
    position: relative;
    overflow: hidden;
}

.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        45deg,
        rgba(255,255,255,0.2) 25%,
        transparent 25%,
        transparent 50%,
        rgba(255,255,255,0.2) 50%,
        rgba(255,255,255,0.2) 75%,
        transparent 75%,
        transparent
    );
    background-size: 30px 30px;
    animation: moveStripes 1s linear infinite;
    pointer-events: none;
}

@keyframes moveStripes {
    0% { background-position: 0 0; }
    100% { background-position: 30px 0; }
}

.playlist {
    margin-top: 20px;
}

.playlist h2 {
    color: #333;
    margin-bottom: 10px;
    font-size: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.song-count {
    background: #667eea;
    color: white;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 14px;
    margin-left: 10px;
}

#playlistContainer {
    min-height: 100px;
    border: 1px dashed #ddd;
    border-radius: 5px;
    padding: 10px;
}

footer {
    text-align: center;
    margin-top: 20px;
    color: #999;
    font-size: 12px;
}

/* Responsive Design */
@media (max-width: 600px) {
    .container {
        padding: 20px;
    }

    .form-group label {
        margin-bottom: 5px;
    }

    .radio-group {
        flex-direction: column;
        gap: 10px;
    }

    .button-group {
        flex-direction: column;
    }

    button {
        width: 100%;
    }

    h1 {
        font-size: 24px;
    }
}

@media (min-width: 601px) and (max-width: 1024px) {
    .container {
        width: 90%;
        padding: 25px;
    }
}

/* Student 2 - Song Item Styles */
.song-item {
    background: white;
    padding: 15px;
    margin-bottom: 10px;
    border-radius: 8px;
    border-left: 4px solid #667eea;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

.song-item:hover {
    transform: translateX(5px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.2);
}

.song-title {
    font-size: 16px;
    font-weight: bold;
    color: #333;
    margin-bottom: 8px;
}

.song-details {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    font-size: 14px;
    color: #666;
}

.song-details span {
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.rating-stars {
    color: #f1c40f;
    letter-spacing: 1px;
}

.rating-badge {
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: bold;
}

.rating-badge.low {
    background: #ff6b6b;
    color: white;
}

.rating-badge.medium {
    background: #feca57;
    color: #333;
}

.rating-badge.high {
    background: #48dbfb;
    color: #333;
}

.video-badge {
    background: #ff6b6b;
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 12px;
}

.empty-playlist {
    text-align: center;
    padding: 30px;
    color: #999;
    font-style: italic;
}

/* Student 3 - Rating Container Styles */
.rating-container {
    position: relative;
    width: 100%;
}

.rating-value {
    position: absolute;
    top: -30px;
    left: 0;
    background: #667eea;
    color: white;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: bold;
    transition: left 0.1s, background 0.3s;
    white-space: nowrap;
    pointer-events: none;
}

.rating-value.low {
    background: #ff6b6b;
}

.rating-value.medium {
    background: #feca57;
    color: #333;
}

.rating-value.high {
    background: #48dbfb;
    color: #333;
}

.rating-value.low::after {
    border-top-color: #ff6b6b;
}

.rating-value.medium::after {
    border-top-color: #feca57;
}

.rating-value.high::after {
    border-top-color: #48dbfb;
}

.rating-value::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 50%;
    transform: translateX(-50%);
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-top: 6px solid #667eea;
}

input[type=range] {
    -webkit-appearance: none;
    width: 100%;
    height: 8px;
    border-radius: 5px;
    background: linear-gradient(to right, #ff6b6b, #feca57, #48dbfb);
    outline: none;
}

input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: white;
    border: 2px solid #667eea;
    cursor: pointer;
    transition: transform 0.2s;
}

input[type=range]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* Student 3 - Notification Styles */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    min-width: 300px;
    max-width: 400px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.2);
    padding: 15px 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    transform: translateX(120%);
    transition: transform 0.3s ease;
    z-index: 1000;
    border-left: 4px solid;
}

.notification.show {
    transform: translateX(0);
}

.notification.hide {
    transform: translateX(120%);
}

.notification-success {
    border-left-color: #4CAF50;
}

.notification-error {
    border-left-color: #f44336;
}

.notification-info {
    border-left-color: #2196F3;
}

.notification-icon {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    flex-shrink: 0;
}

.notification-success .notification-icon {
    background: #4CAF50;
    color: white;
}

.notification-error .notification-icon {
    background: #f44336;
    color: white;
}

.notification-info .notification-icon {
    background: #2196F3;
    color: white;
}

.notification-message {
    flex: 1;
    font-size: 14px;
    color: #333;
}

.notification-close {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: #f0f0f0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    cursor: pointer;
    transition: background 0.2s;
    flex-shrink: 0;
}

.notification-close:hover {
    background: #e0e0e0;
}

/* Student 3 - Tooltip Styles */
[title] {
    position: relative;
    cursor: help;
}

[title]:hover::after {
    content: attr(title);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: #333;
    color: white;
    padding: 5px 10px;
    border-radius: 5px;
    font-size: 12px;
    white-space: nowrap;
    z-index: 10;
    margin-bottom: 5px;
    pointer-events: none;
}

[title]:hover::before {
    content: '';
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 5px solid transparent;
    border-top-color: #333;
    margin-bottom: -5px;
}

/* Student 4 - Keyboard Hint Styles */
.keyboard-hint {
    display: inline-block;
    background: rgba(0,0,0,0.1);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 11px;
    margin-left: 5px;
    font-family: monospace;
    color: #666;
}

/* Duplicate warning style */
.song-item.duplicate-warning {
    border-left-color: #f39c12;
    background: #fff9e6;
}

/* Loading spinner animation */
button.loading {
    pointer-events: none;
    opacity: 0.8;
}

button.loading::before {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    top: 50%;
    left: 50%;
    margin-top: -10px;
    margin-left: -10px;
    border: 3px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}