* {
    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: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    padding: 30px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    font-size: 2.5em;
    color: #667eea;
    margin-bottom: 20px;
    font-weight: 600;
}

.controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.btn-nav {
    background: #667eea;
    color: white;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    font-size: 24px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-nav:hover {
    background: #5568d3;
    transform: scale(1.1);
}

.btn-nav:active {
    transform: scale(0.95);
}

.month-display {
    font-size: 1.5em;
    font-weight: 600;
    color: #333;
    min-width: 200px;
}

.btn-today {
    background: #764ba2;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-today:hover {
    background: #653a8a;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(118, 75, 162, 0.4);
}

.legend {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 25px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
}

.mark {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 16px;
}

.mark.completed {
    background: #10b981;
    color: white;
}

.mark.partial {
    background: #f59e0b;
    color: white;
}

.mark.none {
    background: #e5e7eb;
    border: 2px solid #d1d5db;
}

.calendar {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 8px;
    margin-bottom: 20px;
}

.weekday {
    text-align: center;
    font-weight: 600;
    color: #667eea;
    padding: 12px;
    font-size: 14px;
    background: #f0f4ff;
    border-radius: 8px;
}

.day {
    aspect-ratio: 1;
    border: 2px solid #e5e7eb;
    border-radius: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s ease;
    background: white;
    position: relative;
    padding: 8px;
}

.day:hover {
    border-color: #667eea;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.2);
}

.day.other-month {
    opacity: 0.4;
    background: #f9fafb;
}

.day.today {
    border-color: #667eea;
    background: #f0f4ff;
    font-weight: 600;
}

.day.completed {
    background: #d1fae5;
    border-color: #10b981;
}

.day.completed .day-number {
    color: #065f46;
}

.day.partial {
    background: #fef3c7;
    border-color: #f59e0b;
}

.day.partial .day-number {
    color: #92400e;
}

.day-number {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 4px;
}

.day-mark {
    font-size: 20px;
    font-weight: bold;
    line-height: 1;
}

.day.completed .day-mark {
    color: #10b981;
}

.day.partial .day-mark {
    color: #f59e0b;
}

.instructions {
    text-align: center;
    padding: 15px;
    background: #f0f4ff;
    border-radius: 10px;
    color: #667eea;
    font-size: 14px;
}

@media (max-width: 768px) {
    .container {
        padding: 20px;
    }

    header h1 {
        font-size: 2em;
    }

    .month-display {
        font-size: 1.2em;
        min-width: 150px;
    }

    .calendar {
        gap: 4px;
    }

    .day {
        padding: 4px;
    }

    .day-number {
        font-size: 14px;
    }

    .day-mark {
        font-size: 16px;
    }

    .legend {
        gap: 15px;
    }
}