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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    background-color: #f5f7fa;
    padding: 20px;
    line-height: 1.6;
}

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

h1 {
    text-align: center;
    color: #2d3748;
    margin-bottom: 30px;
    font-size: 2.5em;
}

h2 {
    color: #2d3748;
    margin-bottom: 15px;
    font-size: 1.5em;
    border-bottom: 2px solid #4299e1;
    padding-bottom: 5px;
}

section {
    background: white;
    border-radius: 8px;
    padding: 25px;
    margin-bottom: 25px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.mode-section {
    padding: 10px;
}

.mode-toggle {
    display: flex;
    gap: 0;
    background-color: #e2e8f0;
    border-radius: 8px;
    padding: 4px;
    max-width: 300px;
    margin: 0 auto;
}

.mode-btn {
    flex: 1;
    padding: 10px 20px;
    font-size: 1em;
    border: none;
    background: transparent;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    color: #4a5568;
    transition: all 0.2s;
}

.mode-btn.active {
    background-color: #4299e1;
    color: white;
}

.mode-btn:hover:not(.active) {
    background-color: #cbd5e0;
}

.timer-display {
    font-size: 3em;
    font-weight: bold;
    text-align: center;
    font-family: 'Courier New', monospace;
    color: #2d3748;
    margin: 20px 0;
    padding: 20px;
    background-color: #edf2f7;
    border-radius: 8px;
}

.timer-controls {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin-bottom: 15px;
}

.btn {
    padding: 10px 25px;
    font-size: 1em;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: 600;
    transition: opacity 0.2s;
}

.btn:hover:not(:disabled) {
    opacity: 0.9;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-start {
    background-color: #48bb78;
    color: white;
}

.btn-stop {
    background-color: #f56565;
    color: white;
}

.btn-reset {
    background-color: #a0aec0;
    color: white;
}

.btn-add {
    background-color: #4299e1;
    color: white;
}

.current-task input,
.manual-form input {
    width: 100%;
    padding: 10px;
    font-size: 1em;
    border: 2px solid #e2e8f0;
    border-radius: 5px;
    margin-bottom: 10px;
}

.manual-form {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.manual-form input,
.manual-form select {
    margin-bottom: 0;
    width: 100%;
    padding: 10px;
    font-size: 1em;
    border: 2px solid #e2e8f0;
    border-radius: 5px;
}

.entries-list {
    margin-bottom: 15px;
}

.entry-item {
    display: flex;
    justify-content: space-between;
    padding: 12px;
    background-color: #f7fafc;
    border-left: 4px solid #4299e1;
    margin-bottom: 8px;
    border-radius: 4px;
}

.entry-info {
    flex: 1;
}

.entry-task {
    font-weight: 600;
    color: #2d3748;
}

.entry-details {
    font-size: 0.9em;
    color: #718096;
}

.entry-duration {
    font-weight: 600;
    color: #2d3748;
    font-family: 'Courier New', monospace;
}

.delete-btn {
    background: none;
    border: none;
    color: #f56565;
    cursor: pointer;
    font-size: 1.2em;
    padding: 0 10px;
}

.total-time {
    text-align: right;
    font-size: 1.2em;
    padding-top: 15px;
    border-top: 2px solid #e2e8f0;
}